Week 4 408
Popular in Mammalogy
Popular in Wildlife and Fisheries Science
This 5 page Class Notes was uploaded by Dani on Saturday February 7, 2015. The Class Notes belongs to 408 at Pennsylvania State University taught by Sheriff in Spring2015. Since its upload, it has received 41 views. For similar materials see Mammalogy in Wildlife and Fisheries Science at Pennsylvania State University.
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Date Created: 02/07/15
Order Lagomorpha Sister clade Rodentia o Leporidae 0 000 0 Skull I Supraorbital process I Parietals fenestrated I Postorbital process I Fenestrated rostrum maxillae I Tiny second incisor 12 genus and 62 species 300g pygmy rabbit up to 7kg arctic hare Primarily nocturnal or crepuscuar I Active at nighttwilight Coprophagous reingest soft fecal pellets I Hind gut fermenters Dentition pattern 21 00 32 33 28 Testes become scrotal during the breeding season Rabbits Altricial young Hares precocial young 0 Ochotonidae Pikas O 0 Skull I No supraorbital process I Maxilla with fenestra I Short rostrum I Parietal lacks fenestration I 2nd incisors peg like 1 genus Ochotona and 30 species 100150g mouse sized Gather LARGE hay piles I Used to survive winter In NA they inhabit talus slopes in boreal or alpine areas Males lack scrotum I Testicles descend eventually Dentition pattern 21 00 32 23 26 o Lagomorphs O O 0 Like originated in Asia 13 genera amp 92 species Highly fenestrated skull I Holes in skull 121 dentition pattern I Peg like incisor behind front incisor Large diastema and lack of canines Teeth are hypsodont and lack root I High crown 2215 0 Have unique joint in skull that allows slight movement I Because of saltatorial movement 0 Jumping and hopping 0 Active all year 0 Snowshoe hare o Lagomorpha Leporidae Lepus Lepus americanas 0 White fur in winter and brown fur in summer 0 Biology I Weigh 12001800g relatively small I Home ranges of 510ha I In summer they eat 0 Forbs o Grasses 0 Leaves I In winter they eat 0 Twigs o Bark I Live completely above ground and are crepuscular I Synchronous breeding o All females give birth within 7 days of each other approx May 23rd I Two to four litters per summer with 36 leverets per litter I Gestation of 3537 days and weaning 2428 days I Hares are born precocious I 95 of adult hares die due to predation o 81 leverets die 0 Population cycles I Low phase driven by maternal stress created during decline and maintained during low phase 0 Babies inherit stress from mothers I Rest of cycle heavily influenced by direct predation 2415 Thermoregulation o Endothermy and homeothermy o Mammals are endothermic within heat and homeothermic same heat 0 Very costly and cost increases as temperature decreases 0 Regional heterothermy I Extremities are held at lower temperature than the core I Lowers energy costs 0 Temporal heterothermy I When torpor fluctuates daily or seasonally 0 Advantages I Ability to adapt to large variety of environments I Can be active at any time of day I Maintain very high activity levels Tb Ta 0 O O 0 Ta ambient temperature Tb temperature of the body C conductance V02 oxygen consumption Thermal neutral zone range of ambient temperature in which no metabolic energy is expended to regulate Tb OOOO Postu ring Fluffing or compressing fur Localizing vascular shiftsflow Daily activity Digestion Conductance amount of heat lost to environment 0 0 Can minimize by I Living in warmer environments minimize diff between Tb and Ta I Having more insulation I BERGMANN farther from equator bigger species and ALLEN s Rule extremities longer closer to equator BUT minimizing heat loss may not always be the concern desert animals Critical limits of TNZ O O LCT the point which below metabolic rate must be increased to maintain constant Tb UCT point above which metabolic rate must be increased to maintain Tb Metabolic Rate 0 O V02 CTbTa Basal metabolic rate minimum metabolic rate necessary to sustain maintenance of body within TNZ I At rest but not sleeping I NO digestion I Not reproductive Resting metabolic rate similar to BMR but less strict I At rest difficult to have an animal at perfect rest I Post digestion difficult to have 0 digestion I No reproduction Field metabolic rate animals complete energy expenditure over a 24 hour period I Animal is active and not active I Is resting and not I Is eating foraging running from predators etc Factors affecting MR I Body size mice has higher MR than elephant I Environment 0 Temperature 0 Water 0 Food availability 0 Adaptations to coping with cold 0 In the cold animals face the big challenge of having a large difference between TbTa Must have a high MR 0 Need lots of energy input Food Must have low conductance 0 Strategies to coping with cold Bear it o Involves a combo of O O O Maintaining Tb Extremely high MR Low thermal conductance 0 Strategies to lower cost 0 Hibernate Be big I Large animals conserve heat better I Surface area to volume ratio lower 0 Heat production is roughly proportional to volume 0 Heat loss roughly proportional to surface area I Carry more insulation I Larger animals can carry more energy reserves fat Have tons of insulation I Insulative value of fur increases with thickness I Blubber 0 Does not compress under water 0 Alternative advantages 0 Can dissipate heat 0 Energy storage 0 Aids in buoyancy o Helps in streamlining Only heat what s necessary when it s necessary I Regional heterothermy I Countercurrent heat exchange When necessary behavioral adaptations I Active when it is warmest part of the day I Huddling 0 Alone or in groups 0 The drop in Tb associated with hibernation is NOT hypothermia O Hypo unregulated loss of body temperature 0 How to prepare 0 O O Hibernators gain substantial mass during summer Begin Tb decrease and MR decrease during summer Gather cache 0 During hibernation animal employ 1 of 2 strategies 0 Eat or not eat 0 Why only eat at end of hibernation
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