Introduction to Mammal Diversity Numbers of Species of

Introduction to Mammal Diversity

Numbers of Species of Living Organisms Fungi 72, 000 Algae 40, 000 ? Amphibians 4, 200 Reptiles 6, 300 Flowering Plants 270, 000 Birds 9, 000 Insects 950, 000 Mammals 4, 000

Mammal Numbers Depending on which source you consult: • Total number of mammal species currently identified is between 4, 000 and 5, 500 • 26 to 29 orders of mammals

Notes on mammal evolution • Modern mammals evolved from a group of reptile-like animals 200 million years ago during the Jurassic period • When mammals arose, the earth was all one continent, the climate was warmer, dinosaurs were the dominant animals • First true mammals were small, shrew-like and nocturnal with a well-developed sense of smell (195 million years ago) • Following the Cretaceous-Tertiary extinction 65 million years ago, mammals diversified into many forms we see today

Mammal Taxonomy • • Kingdom Phylum Subphylum Class • • Animalia Chordata Vertebrata Mammalia Monotremes Marsupials Placental Mammals Source: “MSWIII” Wilson, D. E. , and D. M. Reeder (eds). 2005. Mammal Species of the World. Johns Hopkins University Press, 2, 142 pp. (Available from Johns Hopkins University Press, 1 -800 -537 -5487 or (410) 516 -6900 http: //www. press. jhu. edu/. )

Three Major Groups of Mammals Differences in embryonic development: Monotreme: Young hatch from leathery eggs that are similar to reptile eggs. The mammary glands have separate openings (no nipple) and the young lap milk from tufts of fur rather than suckling as in marsupials and placental mammals. Marsupial: Short gestation, no placenta in majority of species, young born early in development, young attach to nipple (often in pouch) to suckle and complete development. Placental Mammal: Longer gestation, young are nourished prior to birth via the placenta attached to the uterus wall. Live birth; young suckle.

Orders of Mammals • Monotremes (5) ü Marsupials—seven orders (331) • Pangolins (8) ü Armadillos (21) • Anteaters, sloths, tamanduas (10) • Rabbits, hares (93) • Rodents (2, 277) • Elephant shrews (15) ü Primates (376) • Tree shrews (20) • Colugos (2) • Bats (1, 116) • Otter shrews, golden moles, tenrecs (51) • Hedgehogs, moonrats, gymnures (24) • Shrews, moles (428) ü Carnivores (287) ü Even-toed ungulates (240) • Whales, dolphins, porpoises (84) • Aardvark (1) ü Odd-toed ungulates (17) • Hyraxes (4) • Manatees, dugongs (5) ü Elephants (3)

Mammal Physical Characteristics Defining characteristics: 1. Hair/fur 2. Production of milk by modified sweat glands, called mammary glands 3. Middle ear consists of chain of three bones; lower jaw is a single bone Mountain goat

Illustration from Occupational and Health Safety Administration www. osha. gov

Other Physical Characteristics of Mammals • • Ectothermic (warm-blooded) Toes end in nails, claws, or hooves Seven vertebrae in neck Different types of teeth: incisors, canines, premolars, molars (number and shape vary); teeth replaced only once Nearly all bear live young (egg-laying mammals are the exception) Four-chambered heart (two ventricles, two auricles) Red blood cells lack nuclei (greater capacity to carry oxygen Larger, more complex and differentiated brain

Mammal Reproduction • Milk is a rich and concentrated food source—allows for rapid growth and maintaining body temperature • Many mammals live in pairs during the mating season; few mammals form permanent pairs Sumatran tigers • Fertilization is internal • Embryo derives nourishment directly from mother (except in monotremes) via the placenta • Mother provides extended care to young

Gestation • Short in marsupials, longer in placental mammals • Length of gestation ranges – usually shorter for smaller mammals and longer for larger mammals • Length also depends on degree of development of newborns • Delayed implantation results in very long gestation (marsupials, bats, shrews, rodents, armadillos, bears, weasels) Koala

Mammal Social Behavior Different types of social groups have evolved depending on food availability, terrain and predators • Solitary societies – ♀ + ♀ ♂ • Polygynous group (harem) – ♂+ ♀ • Permanent groups with complex structure (marsupials, ungulates, elephants, primates and some carnivores) ♀♀♀ – dominant pair – matrilineal Zebra and wildebeest

Mammal Locomotion • • Walking/running Jumping Digging/burrowing Climbing Gliding Flying Swimming Snow leopard Hippos Siamangs

Mammal Senses More than half of all mammals are nocturnal: • all of the approx. 1, 116 species of bats • 80% of marsupials • 60% of carnivores • 40% of rodents • 20% of primates Grey-headed fruit bats

Primary Mammal Senses • Olfactory/Smell – chemical stimulation of odors in the air detected by smell membranes in the nose • Hearing - middle ear structure amplifies mechanical energy from air, which then passes through the fluid of the cochlea and is transferred as nerve impulses to the brain • Sight – more important for diurnal mammals (full color vision only in primates); stereoscopic vision (both eyes facing forward) in carnivores and in primates

More on a few groups of mammals…

Monotreme Characteristics • Egg-laying mammals • Waste/reproductive openings are a single duct (cloaca) • Lack teeth as adults • Found only in Australia and New Guinea Duck-billed platypus Long-beaked echidna

Monotremes • Five species: –Duck-billed platypus –Long-beaked echidna (3 species) –Short-beaked echidna Duck-billed platypus Long-beaked echidna

Marsupial Characteristics • Fenestrated palate—large gaps in roof of mouth • Brain—smaller and more simple than placental mammals • Teeth – Number of incisors in upper jaw different from number in the lower jaw; in placental mammals, the number is equal – Number of molars and premolars different in marsupials than in placentals Tasmanian devil

Marsupials • Found in North and South America, but primarily in Australasia (Australia, New Guinea, nearby islands) • Opossums (North and South America) • Marsupial moles, carnivorous marsupials (Tasmanian devil, numbats, etc. ) • Bandicoots and bilbies • Koala, possums, gliders, wombats, kangaroos, wallabies Opossum Wallaroo

Rodent Characteristics • Found all over the world except Antarctica, New Zealand some oceanic islands • Wide diversity of diets and habitats • Teeth are specialized for gnawing – upper and lower incisors separated from molars by a gap (no canines) – incisors grow continuously – enamel on front surface of incisors but not on back = wears to a chisel Douglas squirrel

Major Groups of Rodents Porcupine • Springhaas • Beaver, kangaroo rats, gophers and relatives • Porcupines, guinea pigs, capybaras and relatives • Mice, rats, gerbils and relatives • Squirrels and relatives Beaver

Bat Characteristics • Found throughout the world, except in polar regions • Only mammal with true wings and flight • Two major ecological groups: – Megachiroptera: eat fruit/nectar/pollen, in Old World tropics, use vision (and thus larger eyes) – Microchiroptera: eat insects (or other carnivorous diet), broadly distributed around the world, use echolocation (and thus larger ears)

Ungulate Characteristics (hoofed mammals) • Large, barrel-shaped bodies • Sideways-facing eyes • Adaptations of teeth: – reduced canines – molars designed for crushing plant material • Thick skin usually covered in hair, not fur • Adaptations of feet: – hooves made of keratin – unguligrade: walk on tiptoes – number of toes reduced to one or three (odd-toed ungulates) or two or four (even-toed ungulates) Japanese serow in Woodland Park Zoo Goat Malayan in Woodland tapir Park in Woodland Zoo Park Zoo

Major Groups of Ungulates • Order Even-toed Ungulates – Pigs, peccaries, hippos – Camels and llamas – Ruminants (deer, giraffe, antelope, gazelles, goats, cattle, sheep, buffalo) • Order Whales, Dolphins, Porpoises – New evidence that whales/ dolphins/ porpoises closely related to Even-toed Ungulates (most closely to hippos) • Order Odd-toed Ungulates – Horses, tapirs, rhinos

Elephants - Physical characteristics • Largest terrestrial animal: average height 11 ft at shoulder and average weight 5 tons (male African savanna elephant) • Second tallest terrestrial animal (after giraffe) • Trunk (fused African savanna elephant and Asian elephant nose and in Woodland Park Zoo upper lip) • Tusks (modified upper incisors) • Mammary glands located between front legs • Large ears

What’s a Carnivore? 1. A member of the order Carnivora: All stem from ancestors that possessed four carnassial teeth: sharp and bladelike upper premolars and lower molars, used for cutting meat and tendon - Most modern Carnivora predators retained carnassials - Carnassials in bears and raccoons became crushing teeth as diets became more omnivorous - Pinnipeds (aren’t always classified as members of the order Carnivora) have reduced or absent carnassials 2. An animal that catches and consumes other animals Non -Carnivora mammals, birds, reptiles, fish, etc - Orcas are mammals that eat a variety of aquatic prey - Raptors are birds that hunt and kill with their feet - Snakes are reptiles that use constriction or venom to kill their prey - Piranha ambush prey in rivers

General Carnivore Characteristics • Extremely diverse group - Smallest carnivore: least weasel at 1 to 2. 5 oz (30 to 70 g) Largest land carnivore: polar bear at 800 to 1400 lb (360 to 635 kg) Largest aquatic carnivore: elephant seal, averages 5000 lb (2270 kg) - Vary from mostly carnivorous diet (jaguars) to mostly herbivorous diet (giant panda). Most will scavenge if given the opportunity. - Some are solitary; others live in packs • Acute senses: excellent vision, hearing and sense of smell

Carnivore Characteristics continued • Built for running: small, suspended collarbone allows for long strides, fused wrist bones provide shock absorption (and support for climbing and grappling) - Some can run long distances, others are rapid sprinters that use their speed to overcome their prey • Territorial: use scentmarking to form territory boundaries - All carnivores have special anal glands that emit secretions, also mark territory with urine • Specialized reproductive anatomy: males in all families, except hyenas, have a penis bone to prolong copulation

Order: Carnivora Family members (common names) Cats Civets, genets African palm civet Mongooses Fossa, Malagasy carnivores Hyenas Aardwolf Dogs, foxes, wolves, coyote Bears Giant panda Raccoons, coatis, kinkajou Red panda Weasels, badgers, otters, fishers, wolverines Skunks Eared seals, sea lions Earless seals Walrus

Primate Characteristics The following apply to most primates: • Opposable first digit on hands and feet • Social animals • Arboreal part or all of the time • Color vision • Omnivorous De. Brazza’s guenons

Primate Characteristics (continued) • Forward facing eyes allows for stereoscopic vision (ability to judge distance) • Five digits on each limbs; usually with nails • Longer gestation, reduced number of offspring • Increased complexity of brain Drawings by Sue Cockrell

Apes Prosimians Primates New World monkeys Old World monkeys

Orders of Mammals in Washington • Marsupials – opossum (1) • Rabbits, hares (8) • Rodents (51) ü Bats (16) Pygmy rabbit • Shrews, moles (12) ü Carnivores (25) ü Even-toed ungulates (7) • Whales, dolphins, porpoises (26) California sea lions *Includes introduced species (9) Source: Burke Museum, http: //www. washington. edu/burkemuseum/collections/mammalogy/ma mwash/mamwash. html

Mammal Conservation One in every four mammals faces a high risk of extinction in the near future (IUCN Species Survival Commission, 2004) Factors leading to species declines: 1. Habitat destruction 2. Introduced species 3. Pollution 4. Over-exploitation 5. Global climate change All these factors are related to human population growth and consumption of resources

Mammal Conservation • Though not the largest group of organisms, mammals represent a wide diversity of adaptations and fill important niches in ecosystems across the planet • Mammals can be “flagship species” for conservation—people identify with and care about cute, furry animals! Endangered mammal photo galleries: • http: //www. iucnredlist. org/info/gallery 2 006 • http: //www. arkive. org/species/GES/ma mmals/

Woodland Park Zoo— 2011 Photo Credits: Photos by Woodland Park Zoo staff: All photos by K. Remine, M. White or J. Mears unless otherwise noted. All photos property of Woodland Park Zoo. All rights reserved. Other photos/illustrations: All echidna photos courtesy of the Tree Kangaroo Conservation Program Primate characteristics illustration by Sue Cockrell All rights reserved. Mexican free-tail bats