Here, again, is an example of the primitive mammalian tribosphenic

cheek tooth pattern (this is the opossum, Didelphis). Identify the

three primary cusps on both upper (protocone, paracone, metacone)

and lower cheek teeth (protoconid, paraconid, metaconid), as

well as the talonid basin on the lower teeth. Note how the protocone

occludes with the talonid. At the rest of the stations, observe the

cheek teeth and note how they have been modified from the primitive

form. What was the primitive eutherian dental formula?

Order Carnivora

Suborder Fissipedia

Family Felidae (feliformia)

Use the domestic cat skeleton to show the typical posture and appearance

of felids. This is a very uniform family, from the smallest (Felis cattus) to the

largest (Felis tigris - tiger; Felis leo - African lion), all look remarkably similar in

body form. The cheetah (Acinonyx), with its small head, exceptionally long legs

and non-retractile claws is the most divergent felid. Other cats tend to have larger

heads (big jaws?) and fully retractile claws (how do they work?). What is the

typical tooth formula of a cat? Can you count it out?

Use the skulls of the modern mountain lion (Felis concolor) and the saber-

toothed cat (Smilodon) to contrast these two major lines of felid evolution.

Family Viverridae and Family Herpestidae (feliformia)

You will notice that in the Mammals of the World, and other mammal books

that the old family Viverridae includes all of the animals now split between these 2

families. The new Family Viverridae consists only of the genets and civets; the

Herpestidae now includes all of the animals we collectively call mongooses. Few

differences distinguish them. All are limited to the Old World, especially in the

tropics. Collectively, they are ecological equivalents of mustelids (see below).

Viverrids are only found in the tropics and south temperate regions (Africa,

southern Europe, southern Asia). They are not highly cursorial; most are generalized

carnivores, feeding on insects and small vertebrates, but some are good climbers

(supplementing their meat diet with fruit) and some are semiaquatic (fish and frogs).

Herpestids are found across the tropics and warm temperate regions of the Old

World (Africa, SE Europe, Middle East, India, SE Asia). The mongooses are smaller

than genets and civets, and have long, skinny bodies similar to weasels. Some are

woodland forms similar to raccoons; some live in quite arid areas. Many are highly

social and live in large colonies. The most familiar are the suricates or meerkats

(Timon from the Lion King). Like many species, they share large underground dens.

They are diurnal, feeding primarily on insects. They use a scouting and alarm system

similar to prairie dogs - one or two individuals sit on an elevated area and constantly

scan for predators while the others forage. If a predator is spotted they give a loud

alarm call and everyone comes rushing back to the den. Use this book to peruse the

wide variety of forms in these Old World families.

Family Hyaenidae (feliformia)

This is the smallest (4 species) and in many ways the most specialized

family of Carnivores. They occur mostly in Africa, but some species range

across SW Asia. It includes 3 species of predatory meat-eaters (the spotted,

striped and brown hyaenas), plus a really weird guy called the aardwolf (see

Walker’s Mammals of the World, p. 1056). The aardwolf is the most special-

ized Carnivore in habits, skull and teeth. It feeds almost exclusively on termites,

so what would you expect its jaws and teeth to be like? What about its canines?

What might they be used for?

The other hyaenas are extremely good predators with very powerful jaws

and sectorial teeth. Their carnassials are not only sharp, but very robust. They

are known to be able to bite through heavy gauge steel containers to get at the

food inside! Though they often scavenge from other predators, they are also

highly skilled hunters, using group hunting techniques similar to wolves or lions.

This makes them very successful competitors for prey.

Order Carnivora

Suborder Fissipedia - caniformia

Family Canidae

The dog family includes foxes (Vulpes & Urocyon), coyotes,

dogs and wolves (Canis), and jackals (also Canis). These animals

are good cursors, but somewhat less specialized as carnivores than

cats. Note the sharp carnassials, but also note the two molars

posterior to the carnassials. Typically the tooth formula is 3-1-4-2

What does the long snout do for the animals? 3-1-4-3

Be able to recognize who is who by skull and skin.

Family Procyonidae (caniformia)

The raccoon family includes also the kinkajou (no specimen), and

the coatimundi (Nasua). These are moderately large omnivores. Procyon

often climbs trees and has a great deal of manual dexterity (note 5 relatively

long toes on each foot). The tooth formula is typically 3-1-4-2 .

Note size and shape of carnassials. 3-1-4-2

Family Mustelidae (caniformia)

Weasels (Mustela), badgers (Taxidea), skunks (Mephitis, Spilogale)

and otters (Lutra) are the most common members of this family of generalized

omnivores. Shortening of the snout is common. The tooth formula is 3-1-3-1 .

Note in Mustela that the upper molar is hourglass shaped. 3-1-3-2

In all of them the posterior molar is much broader than it is long - allowing for

the short snout. How sharp are the carnassials? What does this suggest about

their lifestyles?

Family Ursidae (caniformia)

Bears come in many sizes and shapes, but have generally

gone in for large size and power, losing the cursorial specialities

inherited from their canid ancestors (I still wouldn’t want to have

to out-run one!). Some Asian forms are tropical (sun bear), but bears

have been among the most successful carnivores at invading colder

high temperate and subarctic habitats. Their generalized, omnivorous

habits have allowed them to be successful using a variety of foods;

though some, like the Giant Panda are very selectively specialized.

Note the typical ursid teeth with loss of carnassial function. Note also

that the teeth that were carnassials still show marked elongation, but have

now become bunodont along with the other cheek teeth.

Order Carnivora

Suborder Pinnipedia (caniformia)

Family Otariidae

Sea lions and eared seals have tiny external ear flaps (reduced

pinnae). These and their long, unfurred foreflippers, distinguish the

otariids from the true seals (Phocidae). Otariids are somewhat less

clumsy on land than are the other pinnipeds and can actually walk

quadrupedally using hindflippers and foreflippers. What are the

differences in the way that sea lions swim versus seals?

Sea lions are found throughout the Pacific, Indian and South

Atlantic Oceans. Though quite common in the Northern Pacific, along

the west coast of the US, they do not occur in the Northern Atlantic, so

many of us have not had the opportunity to see them in the wild.

Sexual dimorphism is greatly marked in these highly social

animals. Males are often 2-3X larger than females. What does this

reflect about their social organization and mating habits?

See p. 32 in the Natural History magazine.

Family Odobenidae (caniformia)

This family is now limited to only a single species (Odobenus

rosmarus), the walrus. These huge pinnipeds are the most limited in

range, usually found only in northern latitudes, near the Arctic Circle.

They feed mainly on molluscs, but are known, rarely, to take seals or

cetaceans. Describe their lifestyle and the adaptations for it. In what

ways are they similar to other pinnipeds? In what ways different?

Family Phocidae (caniformia)

True seals are the most successful of the pinnipeds both in

numbers of species and in diversity of their habits. They include both

the smallest of the pinnipeds (harbor seals), as well as the largest

(elephant seals). Unlike otariids, their hindflippers are so modified for

propulsion that they cannot be used on land. They are the most highly

modified for swimming of any of the pinnipeds.

What modifications do they have for diving? Describe the

diversity of feeding styles and how this is reflected in their morphology.

ORDER CETACEA

Suborder Mysticeti - the great whales

The baleen whales are the largest creatures ever to live on earth. The Blue Whale can reach 100' in length and 175 tons! Most are around 30-50' long. Their name comes from the horny, keratinous plates of baleen that hang from the upper jaws in place of teeth. Examine

this piece of baleen. Then look at the pictures in National Geographic to see how the humpback whales feed. All mysticetes are designed to feed by filtering, whether scooping up mud or swimming with the mouth open, etc. This selects for large size, slow swimming, and the ability to find large plankton blooms. This is one reason than mysticetes tend to migrate the furthest distances among whales. Since you don’t need good echolocation to track down this food, however, most mysticetes do not echolocate. They do have good ears and use their voices for impressive communication with each other. There is evidence that their underwater calls can be heard over several hundred miles of open ocean.

Suborder Mysticeti

We will study 3 families from this suborder:

Family Balaenidae - right whales (Northern and Southern right whales & the bowhead) are characterized by huge heads and very long baleen plates. These are primarily colder water animals, occupying No and So temperate, and Northern arctic waters of the Atlantic and Pacific. Great hunting pressure has reduced them to near extinction throughout their range; natives of No America are still permitted to hunt the bowhead whale, but their ancient whale-hunting cultures will undoubtedly die as the whales decline.

Family Eschrichtiidae - gray whales are now reduced to only the Pacific form, which occurs only in the North Pacific (temperate and arctic). They have returned from the brink of extinction twice in the last 150 years, and are now stabilized. Probably because of their habit of migrating close to the western coast of No America, we know more about them and their habits than any of the other great whales. They have a unique feeding style that you should read about in your text.

Family Balaenopteridae - this family of whales, commonly known as rorquals, is most speciose (6) and contains the largest of the great whales. Their name refers to the pleat-like furrows present in the skin of the throat which allows tremendous expansion during feeding. These whales are found in all the seas of the world, and are the only ones to be found in the Antarctic Circle. See the Humpbacks in National Geographic, and the picture of the Blue whales feeding in Audubon, p. 71. Some rorquals like the Mincke whale are moderate in size, but most average over 50', with the giant Blues up to 100' in length.

ORDER CETACEA

Suborder Odontoceti

Not much is known about the origins of the whales. Recent fossil finds are clarifying their ancestry somewhat. Here is a reconstruction of the ancestors of odontocetes. Based on modern

molecular analyses, both odontocetes and mysticetes are now thought to have come from a common ancestor, similar to the Oligocene forms shown here. But where and when they separated from each other is not known.

Toothed whales differ from baleen whale in many ways - obviously baleen whales feed by filtering, whereas toothed whales are carnivores, feeding on fishes, pinnipeds, other cetaceans and large inverts. To do this effectively, odontocetes have evolved complex echolocation abilities second only to bats. In addition, most are fast and highly agile swimmers to chase down their prey. Examine them in Mammals of the World when you get a chance.

Suborder Odontoceti

The toothed whales are much smaller on average than the great whales. Most feed on fish or large invertebrates. We will consider 5 of the families (consult Walker’s Mammals of the World for illustrations):

Family Monodontidae - belugas and narwhals are the two species making up this family. They occur only around the Arctic Circle, and down into Hudson’s Bay and the St. Lawrence River of Canada. They are unique among odontocetes in having normal or reduced numbers of teeth (most odontocetes greatly increase the primitive number). The narwhals have only one upper tooth in each jaw, and no lowers. In the males, one of these upper teeth is greatly elongated into a spirally twisted spear-like structure used, presumably, to spar with other males during mating behavior. This spiral tooth, which may be up to 4' in length, when washed ashore and discovered by humans, may have given rise to the unicorn myth. Belugas do not have these enlarged teeth and they retain all 11 teeth in each jaw. These are the real white whales. Both species are highly social and vocal, using high-pitched melodic songs for which reason the belugas are known as the “canaries of the sea”. Narwhals tend to live only in the open seas throughout the year. Belugas must migrate out to the open sea in the winter, but in summer they come close to shore and often venture far up rivers in search of the fish they most commonly feed on.

Family Physeteridae - the sperm whales include 2 small species (pygmy sperm whales of less than 15'), as well as the giant sperm whale which is the largest toothed whale, reaching over 50'. Their heads are very large and squared-off at the snout due to the exceptionally big melon, called the spermaceti organ (what is its function? See your text, p. 425). The giant sperm whale is known to dive to great depths (>4000') to feed on giant squid. They occur in all oceans of the world.

Family Platanistidae - the long-snouted river dolphins are truly unique in choosing to live in fresh water systems only. They are found in the rivers of India (Ganges), So America (Amazon & Orinoco) and Asia (Mekong, Yangsee). As you would expect, these are small forms, usually less than 6'. They are easily recognized by their extremely long snouts with large numbers of teeth (up to 55/55). They feed on river fishes and many live in quite murky water. As a result, they have extreme adaptations fo excellent echolocation. In most, the eyes are reduced, and, in fact, one species is completely blind.

Family Phocoenidae - porpoises are distinguished from dolphins by their exceptionally short snouts. They are small and occur only in coastal waters, primarily of the northern hemisphere. They feed on fish and a large variety of invertebrates. Their teeth are unique in being rather flat and spatulate, with short custs that give a serrated appearance.

Family Delphinidae - the largest family of cetaceans, the dolphins and their relatives are distributed throughout the world’s oceans. They range in size from some of the small coastal forms (<6') up to the pilot whales (20') and the killer whale (30'). Their habits are also extremely varied. They typically feed on fishes, but the killer whales are known to take penguins, seals, and other whales.

Delphinids are known for their great leaps and for their playful nature. In fact, they are highly social, forming large herds, called pods. These are the most highly studied of the cetaceans with regard to intelligence and echolocation - both of which are well-developed! From them we know that whales are extremely versatile in behaviors and possess great intelligence. Note the structure of the skull in this specimen. Do you see any asymmetries? What might this relate to?