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100 Cards in this Set
- Front
- Back
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Mammalogy Classification |
Is the study of animals within the class mammalia. Kingdom - Animalia Phylum - Chordata Subphylum - Vertebrata Class - Mammalia Subclass - Prototheria or Theria Infraclass - within Theria: Metatheria, Eutheria Order Family Genus Species |
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Primary mammalian characteristics (Soft Anatomy) |
1. Hirsute (have hair) - unique feature of mammals 2. Lactogenic (milk producing) - also unique to mammals 3. Endothermic - internal heat production 4. Viviparous - give live birth 5. Four chambered heart - A complete separation of oxygenated and deoxygenated blood is more efficient and allows increased activity. 6. Enucleated red blood cells - lack nuclei; allowing red blood cells to carry more oxygen. 7. Muscular diaphragm - aids in ventilation of lungs 8. Lack of renal portal system 9. Complex integumentary structures - The skin and related structures make up the integument. The main functions of integumentary structures are protection, water conservation, and insulation. 10. Nitrogenous waste excreted as urea 11. Complex facial dermal tissue 12. Extreme expansion of cerebral cortex - Extreme expansion of the cerebral cortex is directly correlated with increased intelligence in mammals. |
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Mammalogy: early origins |
Aristotle (AD 23-79) developed a classification system that recognized different mammals. In the 1600s we see a rebirth of natural history. Much of the renewed interest came from exploration, particularly of the new world, and trade. Carolus Linneaus (1707-1778) developed the hierarchical classification scheme and binomial nomenclature for naming taxa that is the basis for what we use today. |
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Primary mammalian characteristics (Hard Anatomy) |
1. Double occipital condyles - Having double occipital condyles strengthens the connection between the skull and the vertebrae while simultaneously increasing mobility of the head. 2. Epiphyseal lines on the long bones - joint remains stable while bone is growing 3. Lower jaw made up of 2 dentary bones - increased strength for more efficient foraging. 4. Dentary-squamosal articulation of the jaw bone - a diagnostic character of the first “true mammals”. 5. Three middle ear bones ossicles - derived from the jaw bones of reptilian ancestors 6. Tympanic bone present - supports the ear drums 7. Teeth restricted to the perimeter of the jaw 8. Heterodont dentition - teeth of different shapes and sizes in one mouth serving different functions. 9. Diphyodont dentition - 2 stages: milk teeth and permanent teeth 10. Thoracic ribs only (no lumbar as in reptile) 11. Hard secondary palate - can eat and breathe at the same time 12. Calcaneum (heel bone) present 13. Phalyngeal formula - 2-3-3-3-3 14. Reduced shoulder girdle (1-2 bones) - more mobility |
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Defining vs. diagnosing mammals |
Dr. Tim Rowe defines the first mammal as the last common ancestor to living mammals. He diagnoses the first mammal via the dentary-squamosal articulation of the jaw. Rowe did a good job of settling the debate by creating a definition allows extant mammals to be monophyletic, and then coming up with an appropriate character for diagnosis- i.e., dentary squamosal articulation of the jaw. |
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Synapsida |
The lineage Synapsida, from which mammals evolved, appears in the fossil record approximately 320 million years ago near the end of the Paleozoic era. |
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First true mammals |
Appeared approximately 248 million years ago during the Triassic period (Mesozoic era). |
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Pre-mammalian roots |
The group Amniota includes mammals, reptiles, and birds (the flying reptiles), and their common ancestors with cleidoic (shelled) eggs. The amniotes diverged during the Carboniferous period (360-326 mybp). |
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Tetrapod lineages (four-limbed vertebrates) |
Synapsids branched from the reptilian lineage in the Paleozoic era (about 320 mya). |
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Cenozoic era (65 Mya to present) |
Once the dinosaurs went extinct the mammals underwent a major radiation and replaced the dinosaurs as the major terrestrial vertebrates. The Cenozoic era is therefore known as the “age of the mammals”. |
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Morphological changes of mammals: modern mammals vs modern reptiles |
Reptiles have simple, undifferentiated peg-like teeth (homodont) that are good for grasping and gulping prey, but not chewing. The jaw is made up of multiple bones and articulates with (contacts) the skull in two places in each side. |
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Vertebrate Temporal Fenestrae (Synapsids, Anapsids, Euryapsids, and Diapsids) |
All four groups are distinguishable by the number, size, and position of lateral temporal openings. 1. Synapsids - one temporal opening; led to mammals; postorbital and squamosal bone articulate above hole. 2. Anapsids - no temporal openings; led to turtles. 3. Euryapsids - one temporal opening; led to extinct reptiles, postorbital and squamosal bone articulate below hole. 4. Diapsids - two temporal openings; led to lizards, snakes, and birds. |
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Skull of modern mammals |
The zygomatic arch is composed of the jugal anteriorly and the squamosal posteriorly. The temporal opening is now a large space through which the coronoid process of the lower jaw and muscles for working the jaw pass. |
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Two major groups of Synapsids |
Within the synapsids are two major lineages leading to pelycosaurs and therapsids. Pelycosaurs looked reptilian but as we know, they belonged to a separate lineage from the one containing modern reptiles. The therapsid lineage evolved from a lineage within the pelycosaurs (likely the Sphenacodonts). Therapsids were characterized by a taller, more upright stance and variation in the hind limb stance. |
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Two major groups of Synapsids continued... |
Within the therapsids were two major lineages: anomodonts and theriodonts. Anomodonts were herbivorous and the dicynodonts were the dominant terrestrial herbivore for 60 million years. Theriodonts were much more diverse and primarily carnivorous. |
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Therapsida continued... |
Cynodonts (Cynodontia) were the most diverse and successful of the extinct theriodont lineages. Cynodonts developed many of the transitional anatomical mammalian features leading from “mammal-like reptiles” to mammals. |
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Cynodonts |
These are some of the important transitional features present in cynodonts: 1. Tricuspid, double-rooted cheekteeth with three bumps on the occlusal (chewing) surface and two roots as opposed to a single root. 2. The dentary bone increased in size in conjunction with a reduction in the postdentary bones. Development of the masseter muscles was associated with these changes in the jaw structure. The masseter muscle originates on the lower border of the zygomatic arch and inserts on the lower jaw, and thus plays an important role in chewing for modern mammals. 3. A hard palate separated air intake from food intake. 4. Double occipital condyles provided flexibility in movement of the head. 5. The postdentary bones from the lower jaw were reduced and eventually formed the mammalian inner ear. 6. Major post-cranial skeletal changes include: differentiated vertebrae, particularly the atlas and axis; modified pectoral (shoulder) and pelvic (hip) girdles; and changes in the thoracic ribs and loss of lumbar ribs. |
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Transition from cynodonts to mammals |
1. Body size decreased during the transition between cynodonts and early mammals: mammals did not develop large bodies again until after dinosaurs went extinct. 2. The temporal opening was enlarged in therapsids as compared with pelycosaurs. 3. The squamosal bone dropped down in advanced therapsids and started to look like a zygomatic arch. The zygomatic arch is important for attachment of jaw muscles. 4. Progressive loss of bones in lower jaw. 5. Jaw bones and hinge become bones of the inner ear in mammals. 6. The diagnostic character for mammals is the dentary-squamosal articulation of the jaw. 7. Dentition becomes increasingly complex in mammals, (homodont to heterodont) demonstrating increasingly effective techniques for securing and processing food. 8. Formation of a secondary palate in cynodonts, this change in position allows mammals to run and eat at the same time. 9. There was a shift from a more splayed stance to an upright stance. This allowed more movement and agility, as well as efficiency for sustained speed. |
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Endothermy |
Endothermy has allowed mammals to inhabit extreme habitats. But being endothermic requires a huge increase in need for oxygen as compared to a reptile of similar body size. Mammals also have a large aerobic scope, which is the difference in metabolic rate between complete rest (basal metabolic rate, BMR) and maximum activity (active metabolic rate). |
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Why might endothermy have evolved in mammals? |
One hypothesis is that early mammals were mostly nocturnal because they needed to avoid diurnal predators, and endothermy was a strategy to enable activity even in cold climates at night. Regulating body temperature also allows more precise enzymatic pathways and thus more complex processes. Because of their high BMR and body temperature, mammals are relatively highmaintenance compared to ectotherms. |
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How mammals pay the bill... |
In order to maintain a stable body temperature and high metabolic rate, mammals must have a constant supply of energy and therefore be efficient at accessing food. The basic requirement for maintaining a constant source high energy food is facilitated in mammals by having larger brains (especially true for predators), highly developed sensory perception, and specialized teeth and jaw musculature. Finally, mammals have developed better insulation to help offset the demands of endothermy. |
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Hypotheses for the evolution of endothermy in mammals |
1. One hypothesis is that before true endothermy, inertial homeothermy developed to maintain enzymatic activity. The maintenance of enzymatic activity, and in turn highly specific and complex enzymatic pathways, then enabled the complex structures to arise. 2. Another hypothesis suggests that the increase in brain size required a higher metabolism. The brain requires a huge amount of energy to function. As the brain increased in size, the body had to become more efficient; becoming more efficient enabled further increase in brain size. 3. A third hypothesis suggests that endothermy allowed mammals to be nocturnal, which in turn necessitated acute hearing, olfaction, and thus larger brains. 4. Endothermy allows for higher aerobic activity. Turbinates (scroll-like nasal bones) were present in the nasal cavity of early therapsids. |
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Endothermy in the fossil record |
(Maxillo)turbinates are the scroll-like bones found in the nose of modern mammals. Attachment points for turbinates in early cynodont therapsids thus suggests that endothermy had begun to develop by that point. |
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Significance of lactation |
Lactation was another very important development for early mammals, because it may have facilitated the mammalian pattern of determinate growth. “Determinate growth” describes the pattern of growth characterized by very rapid early growth that reaches a finite maximum size maintained through adult life. In contrast, indeterminate growth refers to growth with no upper limit. Diphyodont dentition is also an important strategy linked to lactation. (Baby teeth and adult teeth) |
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Requirements for lactation... |
1. First, a hard palate is necessary for suckling because otherwise infants could not breathe and suck at the same time. 2. Lactating allows for a high parental investment in nutrition without the need for prolonged gestation. 3. Young can be born relatively small and altricial but still gain nutrition from their mothers that they would not be able to provide for themselves. |
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Prototherian lineage |
Important changes through this period includes: 1. Dentary-squamosal jaw articulation 2. Differentiation of the cheek teeth 3. Increase in ear development 4. Changes in key vertebrae, condyles, and flexibility in spine 5. Mammalian posture |
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Modern mammalian lineages |
Two subclasses: Prototheria, Theria Two Infraclasses within Theria: Metatheria, Eutheria |
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Early Prototherians... |
1. Order Triconodonta: Early prototherians were small and carnivorous or insectivorous. Molars with three cusps arranged in a row. 2. Order Multi-tubur-culata: They were very diverse, but all relatively small. Notice the resemblance to rodents; there was a lot of convergent evolution including a pair of large, procumbent lower incisors and a large diastema (space between teeth). Multituberculates were probable outcompeted by rodents, primates, and other eutherian herbivores. |
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Early Therians... |
Modern therian lineages appear during the mammalian radiation following the extinction of the dinosaurs, break up of Pangaea, and the expansion/diversification of floral diversity ~65 MYA. |
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Early Therians continued... |
Therians emerged toward the end of the Mesozoic, in the Cretaceous period. Mammalian radiation occurred during the early Cenozoic era. Tribosphenic molars characterize early therians and modern marsupials. The tribosphenic molar was multifunctional for both crushing and shearing. Many modern mammals (including humans) have quadritubercular molars- these molars evolved from the tribosphenic molar and are characterized by the addition of a fourth cusp. |
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Phylogeny |
When we refer to the phylogeny of organisms we are referring to their evolutionary history. |
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Taxonomy |
When we refer to taxonomy we are referring to their classification. |
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Systematics |
The science of building evolutionary trees and classifying organisms. The more closely related taxa are, the more traits you would expect them to share in common. In order for a trait to be informative, it MUST be heritable AND variable. Useful traits include morphological characters (e.g., number of cusps on a particular tooth), molecular sequence data, and modes of embryonic development*, to name a few. |
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Systematics: 2 Major methods of tree building |
1. Phenetics involves grouping organisms based on shared similarities, or phenotypes. (traditional method) 2. Cladistics instead groups organisms by shared, derived traits (synapomorphies) and is the most common modern method. |
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Cladistics |
Organisms grouped together using only traits that are: 1. Shared due to common descent 2. Derived relative to an outgroup Synapomorphies are used to identify monophyletic clades. |
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Synapomorphy |
Hair is a synapomorphy for mammals relative to other vertebrates (reptiles, fish) |
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Symplesiomorphy |
However, hair is not a synapormophy for any single group of mammals within Mammalia‐ because all mammals have hair at some point in their development. Thus, within mammals, hair is a symplesiomorphy (a shared ancestral character) and is not informative in a phylogenetic analysis that attempts to resolve, for instance, the evolutionary history of the mammalian orders. |
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Parsimony |
Parsimony assumes that the simplest explanation is most likely the correct explanation. In other words, we arrange taxa in different ways and ask: which arrangement results in the fewest examples of convergent evolution or reversals? That arrangement (the most parsimonious) probably won’t be exactly right, but it hopefully will be close to the truth. |
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Homology |
Homology: similar traits resulting from shared ancestry. All bats and only bats can fly. |
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Homoplasy |
Homoplasy: similar, derived traits due to convergent evolution or reversal. Evidence suggests that flight only evolved once in mammals and thus is a homologous trait. |
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Convergent example... |
Convergent evolution/homoplasy ‐ Cetaceans and sirenians lack hind limbs and have tail flukes; both characters evolved independently. Colugos, flying squirrels, and gliding marsupials have similar structures adapted for gliding. We know that they are the result of convergent evolution because we have lots of other characters that make it clear that they are only very distantly related. Gliding evolved multiple times within mammals and thus is an example of homoplasy. |
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Reversal example... |
Reversal ‐ Adult whales lack hair, although their ancestors had hair as adults (like other mammals). |
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Order Monotremata |
* Subclass Prototheria * Monotremata have one opening i.e. cloaca * Oviparous - lay eggs; reduced investment in gestation, but heavy investment in lactation. * No teats: instead, milk oozes from glands and the young lap it up. * Retain significant number of seemingly reptilian features * Males have rear spurs (some inject poison) |
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Monotreme characteristics |
Reptilian: Lay eggs; complex pectoral girdle; posture; cloaca; venom Mammalian: Furred (no vibrissae); homeothermic; 4-chambered heart; single dentary; 3-middle ear bones; lactation (no teats) |
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Monotremes (distribution and value) |
Restricted to Australia, New Guinea, and Tasmania; not of direct economic importance; conservation status is relatively secure. |
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Monotreme (Ornithorhynchidae skull) |
Family: Ornitho-rhynchidae * The platypus has five digits (pentadactyl) with partial webbing on the hind feet and full webbing on the fore feet. * At home in the water; (semiaquatic and semifossorial) * Distinctive bill with sensory mucous glands - used in foraging. * Burrowing * No pouch * Lactation last 4-5 months Family: Tachy-glossidae * Echidnas are terrestrial * Endentate (lack teeth) throughout development) * Long beak with electroreceptors * Long sticky tongue * Echidnas have a pouch in which the eggs are incubated and young carried until their spines begin to develop. * Eats ants and insects
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Marsupials |
Subclass Theria Infraclass Metatheria * Vivaparious: give birth to live young; young are altricial and weigh1% or less of the mother’s body weight. Marsupial mothers invest heavily in lactation. * The name marsupial is derived from the term “marsupium”, meaning pouch. Despite the name, not all marsupials have a marsupium. * Today marsupials are found in North America, Central America, South America, and Australasia. * Many are terrestrial, arboreal, and at leas one is semi-aquatic. * The fossil evidence suggests marsupials arose in North America. |
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Marsupials (value and status) |
* Many marsupial species are threatened or endangered particularly as a result of introduced, exotic species and habitat destruction. * Invasive in some cases (crop or livestock pests) * Benefit humans as food, fur/hides, ecotourism |
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Marsupial (Reproduction) |
* Females have two lateral vaginae on either side of a vaginal canal. * Males have a bifurcated penis and in two New World families males even have paired sperm. * The short gestation period and altricial condition of young are associated with the structure of the placenta (which is nowhere near as developed as it is for “placental” mammals). * Not only do not all marsupials have a pouch, but the size, shape, and arrangement of pouches varies among species. Pouches protects extremely vulnerable young. |
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Metatheria characteristics |
* Dentition - polyprotodont or diprotodont * Digits - didactylous or syndactylous * Occlusal surface of upper molars * Paired sperm (present or absent) Polyprotodont: lower incisors many and equal in size. Diprotodont: medial incisors greatly enlarged. Posterior incisors small or absent. Didactylous: unfused digits, each toe has its own skin sheath. Syndactylous: skeletal elements of the 2nd and 3rd toes fused, with both toes in a common skin sheath. |
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New world Order (Americas): Didelphi-morphia |
1 Family: Didelphidae (Virginia opossum) They exhibit a variety of life histories and occupy almost all habitats from deserts to tropical forests. They are generally solitary and opportunistic feeders. |
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New world Order: Pauci-tuber-culata |
1 Family: Caenolestidae (shrew or rat opossums) * shrew‐like in appearance * They lack a marsupium and have procumbent, diprotodont lower incisors. Like didelphids, they have paired sperm |
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New world Order: Micro-bio-theria |
1 Family: Micro-bio-theriidae (monito del monte) * Small and mouse‐like with a furred, prehensile tail. They have inflated auditory bullae‐ a rare feature in marsupials. * The monito del monte is nocturnal, arboreal, and found in humid forests of Chile and Argentina. They primarily eat invertebrates, but occasionally will eat herbaceous material. They hibernate and can double their body mass in a single week prior to hibernation! |
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Australasian Order: Dasy-uro-morphia |
The order Dasyuromorphia includes three families, but only two remain. They are polyprotodont, didactylous, and mostly carnivorous. They have well developed canines and some members have specialized carnassial teeth similar to eutherian carnivores (convergence). 3 Families: 1. Thyla-cinidae: Recently extinct Tasmanian wolf. The thylacine was driven to extinction by persecution from ranchers and disease from exotic species. 2. Myrme-cobiidae: includes the numbat; As their name suggests, they are ant specialists (myrmeco = ant in Greek). They have more teeth than any other metatherian. 3. Dasy-uridae: includes the Tasmanian devil; Dasyurids are nocturnal and generally solitary. Members of this family include the smallest marsupial, the Pilbara ningaui, and the largest extant marsupial carnivore, the Tasmanian devil. Several species are endangered. |
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Australasian Order: Pera-mele-morphia |
2 Families: * The bandicoots (Peramelidae); and bilbies (Thylacomyidae) * terrestrial omnivores * chorioallantoic placenta similar to eutherians * short, compact, rounded rostrum * burrowers * polyprotodont * marsupium |
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Australasian Order: Dipro-to-dontia |
11 Families: * includes kangaroos, koala, wombats, possums * diprodont * Most species are herbivorous, but some are specialists or omnivorous * marsupium * syndactylus digits * specialized modes of locomotion including the arboreal adaptions, saltatorial adaptations (e.g., kangaroos), and gliding adaptations (e.g., gliding possums). |
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Australasian Order: Not-orycte-morphia |
1 Family: Notoryctidae (marsupial moles) * only truly fossorial marsupials. They “swim” through the ground with their torpedo‐ like bodies and highly specialized, scoop‐like forearms. * They have a thick, keratinized nasal shield, vestigial eyes, and lack pinnae. * They eat invertebrate eggs and larvae. * zalambdodont dentition (v-shaped) * marsupium |
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Metatharians (marsupial) reproduction |
* short gestation compared to eutherians * long, expensive lactation * Metatherian embryos start off with an egg shell and large yolk sack that provides early nutrition. The shell is resorbed and the embryo implants on the uterine wall. * Metatherians have a choriovitelline placenta that lack villi and therefore is only capable of a weak mechanical connection with the uterine lining. * lack a trophoblast * In marsupials, the estrous cycle is not interrupted by pregnancy. |
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Eutherian (placental) reproduction |
* long gestation time * faster embryonic development * shorter lactation time * estrous cycle is interrupted by pregnancy. * embryo has a small yolk sac, nutrients from mother after it implants on the uterine wall * embryo has a trophoblast: facilitates gas and nutrient exchange and protects the fetus from the mother’s immune system. |
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Difference in gestation time: Metatherain vs. Eutherian |
A long gestation allows for more precocial young. Precocial young tend to be less vulnerable. However, a short gestation period may be beneficial in unpredictable environments. If a female marsupial gets pregnant and there are not enough resources available to support her offspring, she has not invested very much energy and therefore does not lose much by aborting or abandoning her offspring. A long gestation period requires accurate timing; there must be food available months down the road when the baby is born. |
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Insectivores |
Subclass Theria Infraclass Eutheria Five Orders |
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Order Afro-soricida |
2 Families: 1. Tenrecidae (tenrecs and otter shrews) * They generally have low body temperatures and some are heterothermic. Some species may even echolocate. One common feature among tenrecs is the lack of auditory bullae. 2. Chryso-chloridae (golden moles) * They live in dry habitats with loose soil and almost no water. They make up for this lack of water with well developed kidneys, low metabolic rate, nocturnal behavior, and periods of torpidity. many adaptations for living underground such as a leathery pad on their nose, fused eyelids, no pinnae, and large claws. Have truly iridescent pelage. |
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Order Eulipotyphla |
4 Families 1. Erin-aceidae (hedgehogs and gymnures) * Hedgehogs have barbless spines * They are found in Africa, Europe, and Asia including many of the Southeast Asian islands. * most are terrestrial, however some are semi‐arboreal * Special “drawstring” muscles, the panniculus carnosus, help them curl up tightly. * omnivorous 2. Solen-odon-tidae (solenodon) * among the largest insectivores * long pinnae, hair, claws, and naked tails * fossorial * produce toxins * omnivorous and likely echolocate 3. Talpidae (true moles, shrew moles, and desmans) * fossorial lifestyle * short, powerful forearms, short pelage, minute eyes, and fusiform bodies * shrew-moles are terrestrial * desmans semi-aquatic * talpids have specialized sensory abilities and some echolocate * insectivores 4. Soricidae (2 subfamilies: red-toothed shrews and white-toothed shrews) * unique dentition - upper incisors are large, hooked, and have a posterior cusp that looks like another small tooth. Their first lower incisors are long and procumbent. * Shrews lack a zygomatic arch and auditory bullae. * high mass‐specific metabolic rate * insectivorous, although many are functionally omnivorous * produce toxins * echolocate and caravanning behavior |
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Order Macro-scelidea |
1 Family Macro-scelid-idae (elephant shrews) * long flexible snout and long hind limbs * large eyes and ears * central and eastern Africa * terrestrial * generally diurnal but become increasing nocturnal during hot weather * experience short bouts of torpor * socially monogamous |
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Order Scandentia |
* (treeshrews) * seed-dispersers * pentadactyl feet with long claws adapted for climbing * endangered as a result of habitat loss associated with logging and forest clearing for mining * once thought to be primitive primates * Forests, mostly diurnal, omnivorous including fruit
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Order Dermoptera |
1 Family Cyno-cephalidae (colugos) * gliders - extensive patagium including digits * arboreal forest dwellers * primarily nocturnal * eat flowers, leaves, and fruits * procumbent pectinate (comb-like) incisors * were considered primitive primates
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Order Chiroptera |
* Bats are the only truly volant (flying) mammals * Most are insectivorous, but there are also carnivorous, piscivorous, nectivorous, frugivorous, and sanguivorous bats. * long life spans and low reproductive potential * Contrary to popular belief, bats can see and many can see very well. * believed they evolved from shrew‐like insectivores * likely a monophyletic group * Flight enabled bats to occupy “open niches” and diversify rapidly. * reduced skeletal morphology such as a reduction in the rib cage and ulna. * keeled sternum for attachment of large pectoral muscles (for flapping wings) * membrane that makes up the wing is called the patagium and the membrane between the legs, if present, is called the uropatagium |
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Suborder Mega-chiroptera |
* Old world fruit bats * single family: Ptero-podidae * larger in size than Microchiroptera * some are diurnal * simple echolocation only in one genus, used for navigation as opposed to locating prey. * (fox-like) face
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Suborder Micro-chiroptera |
17 families * advanced echolocation in some families, used for navigation and locating prey * diverse diets: small mammals (including other bats) and birds to insects, fruit, nectar, and obligate blood feeders * elaborate facial structures related to echolocation |
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Conservation (bats) |
* many species are threatened - habitat destruction - roost/hibernacula disturbance - eaten by humans (Pteropodidae) - white-nose syndrome * transmit disease * vampire bats kill livestock * very important as pollinators and insect predators
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Bat wing design |
* A high aspect ratio, characterized by long, skinny wings, is optimal for fast, sustained flight. A low aspect ratio is associated with slow, highly maneuverable flight. * Lower wing loading, characterized by low body mass relative to wing surface area, enables carrying of food but with slower flight. * The greater the camber and angle of attack, the more lift that can be produced. |
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Bat design - variation to exploit different nocturnal and aerial niches |
* Hawking: Hunting small, high‐flying insects * Hunting insects among vegetation and gleaning * Fly‐catching or perch and seek * Hunting insects in open habitat * Piscivory: Fish eating * Carnivory, nectivory, sanguivory, frugivory |
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Echolocation |
* use of sound waves and echoes (return of those sound waves back to its source) for orientation and hunting * bats can obtain extremely detailed information on size, shape, distance, movement, texture, and in some instances internal structure of prey in their surroundings. * Echolocation does not have to be as complex for navigation as for hunting. |
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Advantages and disadvantage of echolocation |
* ability to hunt and navigate at night. * bats avoid predators by hiding from vision‐oriented predators in caves or tree roosts. * ability to hunt insects at night opened up an enormous feeding niche * One disadvantage of echolocation is that bats are essentially advertising their presence to anyone that can detect their calls. |
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Echolocation continued... |
* Bats use high frequency sounds in echolocation * less “noise” associated with higher frequency calls, the small body size of bats facilitates production of short wavelengths, and prey items tend to be small sized as well. |
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Sound emission in bats |
* emit sound through mouth or nose * Bat echolocation calls are extremely loud! * In order to protect their ears, bats tighten up their hearing apparatus when emitting calls and relax their hearing apparatus in between echolocation calls, or clicks. * some bats have large, complex pinnae (external ear) and leaf‐like nose projections specialized for focusing and receiving sound. |
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Doppler effect |
* Constant frequency (CF) calls are very good for detecting movement because of the Doppler effect. If the focal object is moving away from the bat (top), the echo will have a lower frequency than the original call. In contrast, if the focal object is moving toward the bat (bottom), the echo will have a higher frequency than the original call. * Frequency modulated (FM) calls do provide a high degree of detail about the target because there are a range of frequencies/wavelengths per call that each return slightly different information. * Constant frequency: used in “Searching phase” while looking for prey. * During the attack phase the bats uses a “terminal buzz”, many short frequency modulated calls, to zero in. |
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Habitat partitioning (bats) |
* Above the canopy, open habitat; long, narrow wings specialized for speed; low, relatively constant frequency call. * Among cluttered vegetation; short, broad wings specialized for maneuverability; medium frequency with some modulation. * In forest gaps; short, broad wings specialized for maneuverability; medium to high frequency modulated calls. |
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Gleaners |
* larger ears, fly slow * short, thick wings * use long CF or steep FM pulses of high frequency (detect movement and minimize noise) |
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Open air insectivores |
* small ears, fly fast * long, skinny wings * use low frequency FM pulses * maximize range |
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Evolutionary arms race |
Some moths can hear bat echolocation calls, while others can produce sounds that jam the bats echolocation calls. |
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Primate characteristics |
* characteristics of primates are associated with an arboreal lifestyle * forelimbs modified for grasping with flexible shoulder joints, opposable digits, nails replacing claws, and sensitive pads on the digits with friction ridges. * reduction in muzzle (snout) size and the olfactory lobes in the brain (reduced sense of smell). * vision and associated structures are well developed in primates: forward facing eyes and color vision in many species. * increased cerebral cortex associated with increased intelligence. * long lived and slow reproductive rates * complex socio‐spatial and breeding patterns * diet of fruits, seeds, and foliage |
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Primate evolution |
* The arboreal theory (i.e., primates evolved as arboreal specialists) explains many primate adaptations including as large, forward facing eyes associated with stereoscopic vision and a large visual cortex, adaptation of the limbs and digits for safe and easy movement in trees, and use of hands instead of the mouth as the primary means of gathering and handling food. * quadrituburcular molars for grinding and crushing |
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Where do primates occur and why? |
* primates are found mostly in the tropics. * They need high quality food, especially fruit, to be available year‐round. |
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Suborder Strep-sir-hini |
4 Families * primitive primates (monophyletic group) * rhinarium (an area of moist, hairless skin around the nostrils similar to that of a dog). One character that distinguishes strepsirhine from haplorhine primates. * when comparing skulls the postorbital bar (as opposed to a post‐orbital plate) is a good cranial feature for distinguishing strepsirhine primates. * pectinate lower incisors exhibited by strepsirhines 1. Lemuridae (Lemurs) * found only on Madagascar * diurnal or crepuscular and mostly arboreal 2. Lorisidae (Lorises, angwantibos, and pottos) * arboreal and nocturnal * sub‐Saharan Africa to India, Southeast Asia, Indonesia, and the Philippines 3. Galagidae (Bushbabies) * found across much of sub‐Saharan Africa * nocturnal and have amazing jumping abilities 4. Dauben-toniidae (aye aye) * found on Madagascar * long fingers and a single long, wire‐like claw on the middle finger that is used for extracting insects from wood. * associated with death and bad luck |
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Suborder Haplo-rhini |
3 Major groups: Tarsiers, old world monkeys and apes, new world monkeys * postorbital plate and spatulate incisors * lack a rhinarium * rounded cranium 8 Families Tarsiidae (tarsiers) * nocturnal * postorbital “plate” is incomplete; it has holes in it and thus is an intermediate structure between a postorbital bar and a postorbital plate. New World Monkeys * Cebidae (marmosetes, capuchins, squirrel monkeys) * Aotidae (night monkeys) * Atelidae (spider and howler monkeys) * Pitheciidae (saki monkeys) * Central and South America * prehensile tails sometimes as long as their bodies * intensely persecuted for food and extirpated over large areas of their former range. Old World Monkeys Cerco-pithe-cidae * Africa and southern Asia * large canines on males * Baboons are major crop‐raiders and can take even fairly large mammalian prey such as small antelope. * considered a “mesopredator” in some cases‐ predators that are normally suppressed by other larger predators but are “released” when the large predators are removed from the landscape. Apes Hylo-batidae (gibbons) Hominidae (Gorilla, Pongo, Pan, Homo) * Hylobatidae includes ten species of gibbons found in southeast Asia and parts of the Malay Archipelago. * Members of the family Hominidae are the largest bodied primates. All members of this family lack tails. They also have the longest developmental period compared to other primates (time to sexual maturity), and all exhibit significant sexual dimorphism with males larger than females. |
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4 myrmecophagous orders "ant eating orders" characteristics |
* Simple teeth * Low BMR * Poor diets (ants, termites, leafy vegetation) * Low body temperatures * Poor thermoregulation |
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Order Cingulata (armadillos) |
* Teeth very reduced * Low metabolic rates (restricted to warmer climates) * Found to carry leprosy * Burrow and eat insects * Poor eyesight |
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Order Pilosa (anteaters and tree sloths) |
Sloths * arboreal foliavores (leaf eating) * Low body temperatures * Poor thermoregulation * Slow movement due to poor diet Anteaters * They lack teeth, havea long, tapered skull with an elongated rostrum, an extremely long tongue, and enormoussalivary glands * huge claws and powerfulforearms designed to rip open termite mounds and a long pointy rostrum to slurp termitesout of cracks * The silky anteater (pictured at right) is small,nocturnal, arboreal, and has a prehensile tail. It has fine, wooly pelage from which itderives its common name. |
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Order Pholidota (Pangolins) |
* not a highly successful group * They have adaptations for myrmecophagy such as a conical skull,lack of teeth, and a long tongue. Their “scales” are modified hair. They have limited vocal,visual, and auditory acuity, but well developed olfaction. They have a strong smelling scentproduced in anal glands that they use for communication. |
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Order Tubulidentata (aardvark) |
* The name aardvark is Afrikaans for “earth pig” * Aardvarks are fossorial; they dig huge burrow systems with multiple openings that manyspecies such as bat‐eared foxes, warthogs, and other smaller mammals make use of. Theyare predominantly nocturnal and use their highly acute olfactory and auditory senses tolocate ants, larvae, locust, and other prey. |
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Order Carnivora characteristics |
* A high brain-to-body mass ratio is associated with high brain capacity * complex spatial navigation and well-developed senses * Well-defined canine teeth * well-developed carnassial teeth * mandibular processes are oriented across the axis of thejaw for a stable hinge joint. These adaptations result in a very strong and efficient bite. * Males have an os baculum, or penis bone. Females of many of the species in this orderexhibit induced ovulation * anal glands for scent marking * Large auditory bullae * Carnassial teeth are specialized for shearing. * Carnivores exhibit a variety of foraging habits. Some, like skunks and weasels, are always onthe move looking for opportunistic prey and forage. Cats are often ambush predators, or acombination of sit and wait and coursing |
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Suborders of Carnivora |
Feliformia Family: Felidae (Cats) * kill their prey by suffocating orbreaking the necks * All cats, except cheetahs, have protractable claws * Cheetahs are unusual in Felidae because they are coursing predators; theyuse their claws for traction while running. Family: Hyaenidae (Hyenas, Aardwolf) * Hyenas are specialized scavengers and carrion feeders with large teeth capable of shearing andcrushing bone. * Females have an enlarged clitoris (referred to as a pseudopenis) and a fleshy padresembling a scrotum * Aardwolves are specialized termite predators. Aardwolves lack carnassial teeth and insteadhave a reduced number of more peg-like teeth. Family: Herpestidae (Mongooses) * Like domestic cats, they are invasive predators on theseislands and in conjunction with rats have decimated many native bird populations. Family: Viverridae (civets and genets) * Genets and civets are small- to medium-bodied and superficially resemble procyonids withtheir spots and stripes. They exhibit a variety of foraging habits. They have perianal glandsthat release a strong smelling fluid. * create large “latrines”, or areas that they visit nightly and defecate. |
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Suborders of Carnivora continued... |
Caniformia Family: Canidae (Dogs, wolves, foxes, dingoes, jackals) * Dogs have been commensal (closely associated) with humans for thousands of years. * Members ofthis family have teeth less specialized for meat eating; they have crushing rather thanslicing molars and some species are somewhat omnivorous. Four species (wolves and wilddogs) exhibit pack living and cooperative hunting. Family: Mustelidae (Weasels, badgers, otters wolverine) * Mustelids typicallyhave long, tubular bodies with short legs. * Mustelids are not particularly good thermoregulators, but they are very active and agilepredators. Family: Mephitidae (skunks and stink badgers) * They are nocturnal, solitary, and highly omnivorous. * When threatened they spray anoxious liquid Family: Procyonidae (raccoon, ringtail, coatimundi) * They have generalized dentition and areomnivorous. Social behavior ranges from mostly solitary (kinkajou) to highly social (whitenosedcoati) Family: Ursidae (bears, and giant panda) * largest terrestrial carnivores * They do not have well-developed carnassial teeth because they are quiteomnivorous * giant panda which is almost exclusively herbivorous Family: Ailuridae (red panda) * The family Ailuridae is monotypic. The red panda lives in the Himalayan Mountains Family: Pinnipeds (walrus, eared seals, and earless seals) * Limbs modified to flippers for swimming * Large eyes modified to focus underwater * Thick vibrissae (whiskers) * Short or absent tails * A thick layer of blubber for insulation * Homodont cheek teeth * Nostrils are closed slits to prevent water from entering Family: Odobenidae (walrus) * circumpolardistribution and are associated with ice floes and rocky shorelines of the arctic * Both sexes have enlarged upper canines (tusks) used to dig for mollusks, their main foodsource; to hang onto the ice; and in intraspecific combat. Family: Otariidae (eared seals) * often colonial, malestend to be significantly larger than females (sexually dimorphic). Family: Phocidae (earless seals) * “true” seals, they arediverse in size and include the largest member of the order: the elephant seal. |
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Order Rodentia (Rodents) characteristics |
* ever‐growing incisors speciallyadapted for gnawing and a diastema without canines between the incisors and cheek teeth
* mostly herbivorous * Rodents are excellent dispersers * rodents exhibit relatively little morphological diversity, there is considerable diversityin feeding strategies, life histories, locomotion, and habitat specializations. * Key diagnostic characteristics for rodents include a single pair of ever‐growing upper andlower incisors, a diastema, and reduced number of molariform cheekteeth. |
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Classifications within Rodentia (based on skull structure and musculature) |
* The protrogomorphic form (A) is considered a primitiveform and is only found in the monotypic family Aplodontidae (mountain beavers of thePacific Northwest‐ not related to beavers). * The sciuromorphic form (B) is characterized by large, flat muscle attachment surfacesincluding a zygomatic plate. * The myomorphic form (C) is characterized by a slightly largerinfraorbital foramen allowing the masseter muscle to pass through from its point of originon the rostrum. * The hystricomorphic form (D) is characterized by a huge infraorbitalforamen. * Lower Jaw Morphology: * Sciurognathous: rodents (A & C)have a relatively simple, v‐shaped jaw with the masseter muscle inserting directly ventral tothe cheek teeth. * Hystricognathus rodents (B & D ) have a strongly deflected angular process and a flangelike,or ridged mandible. The masseter inserts ventral and posterior to the cheek teeth. * As previously mentioned, orientation of the mandibular condyle allows rodents to shifttheir lower jaw forward or backward to enable gnawing (incisors) or grinding (cheek teeth). |
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Rodentia diet |
* Most rodents are herbivorous (vegetation) or granivorous (seeds), however some areinsectivorous, partially carnivorous, or specialists on lichens and fungi. |
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Rodentia life histories |
* In habitats where food is only seasonally available, rodents have developed variousstrategies for dealing with long periods of low productivity. In cold climates rodents oftengo into torpor or hibernation where they greatly slow or almost shut down theirmetabolism completely. Some species, such as groundhogs (Marmota monax), can lowertheir body temperature to near freezing. In hot and/or dry climates rodents may estivate,slowing down their metabolic rate. Many rodents burrow to escape both the heat and thecold. Burrows are often used for food storage as well. * Male rodents have bacula and many, but not all females are induced ovulators. * Many rodents have altricial young. The trade‐off in having a shorter gestation time, andthus less developed offspring at time of birth, means an increased investment in lactation. * In general, animals at higher latitudes (more temperate) have larger litters. |
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Rodentia Families |
Sciurognathous:
Family: Sciuridae (Prairie dogs, groundhogs, chipmunks, flying squirrels, ground squirrels, tree squirrels) * some are consideredagricultural pests Family: Castoridae (beavers) * Beavers have valuable fur and played an important role in the Europeancolonization of Oregon and the Pacific Northwest. * Beavers are ecosystem engineers because they build dams to create ponds. Theycan also cause damage to timber stands by tearing up trees and cause floodingby blocking up culverts and other flowing water. Family: Muridae (mice, rats, and gerbils) * They are very important pest species, disease vectors,and exotic predators. Many extinctions and near extinctions of island birds are attributableto introduced rats and mice depredating eggs and chicks. Family: Cricetidae (voles, lemmings, new world rats and mice) * Many are agricultural pests in fields and by getting into food stores, as well aspests in our homes. * They are extremely important prey species. * Some are reservoirs or vectors for diseases such as Lyme disease and Hanta virus. Hystricognathus: Family: Erethizontidae (porcupines) * Porcupines cause timber damage by girdling trees. * Their guard hairs are modified into quills with barbs * The North American porcupine is terrestrial and semiarboreal while SouthAmerican species are mostly arboreal and have prehensile tails. Family: Myocastoridae (nutria) * They can be major pests as they often dig into levees and dikes. While the furindustry has declined in North America, coypus are still harvested for fur in their nativeSouth America. |
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Order Lagomorpha (rabbits, hares, and pikas) characteristics |
* They represent a significant contribution to environmental biomass and in certainsituations can achieve very high densities. They are important prey species. * Lagomorphs are morphologically similar to rodents * herbivorous and coprophagous. Coprophagy increases their ability todigest low quality vegetation. * Coprophagy: the habit of eating ones own feces. * Lagomorphs have a large cecum that acts as a fermentation chamber where microbesaid in digestion. The cecum is post‐stomach, so the feces must be re‐ingested to absorbnutrients. Coprophagy maximizes the digestion of tough, low quality plant material and alsoprovides another valuable source of nutrition from the microbes themselves. |
