Order Artiodactyla (Even-toed ungulates) Artiodactyls are the even-toed ungulates. They are called even-toed because the third and fourth digits make contact with the ground (in contrast to the Perissodactyla (e.g., horses, rhinoceros) in which only the middle digit makes contact with the ground. The native artiodactylas are all ruminants, and members of 3 families.   Family Antilocapridae (Pronghorn antelope) (family / genus page)
. Antilocaprids are represented by a single species, the pronghorn antelope (Antilocapra americana). Some authorities do not recognize this family and consider the species a member of the Bovidae. Family Bovidae (Cow family) (family / genus page) The Bovids were originally represented in Minnesota by the bison (Bison bison). Bison are now present in Minnesota as captive herds Family Cervidae (Deer family) (family / genus page) The Cervids are represented by moose (Alces alces) and white-tailed deer (Odocoileus virginianus) as the most common species. Other species either present rarely, as visitors, or extirpated include the mule deer (Odocoileus hemionus), elk or wapiti (Cervus elaphus), and caribou (Rangifer tarandus). There are examples of most of these species on the table in one form or another. Note the relative sizes and shapes of antlers in the figure from Geist (1999) as well. Only males grow antlers, except for in caribou. There are no upper incisors in cervids. Order Carnivora (Carnivores) Minnesota Carnivora all have obvious upper and lower canines, and all have 3 upper and lower incisors. The P4 and m1 carnassial pair is present in meat-eating Minnesota Carnivora, less obvious as a carnassial pair in bear and raccoon. Family Canidae (Dog family) (family / genus page) Minnesota canids include the gray wolf, the coyote, the red fox, and the gray fox. Some authorities place all Minnesota canids in a single genus, Canis. All Minnesota canids have a tooth formula of 3/3, 1/1, 4/4, 2/3 x 2 = 42. Family Felidae (Cat family) (family / genus page) The cat family, or Felids. Felids in Minnesota, other than the domestic cat (Felis catus), are the bobcat (Lynx rufus), Canada lynx (Lynx canadensis), and mountain lion (Felis concolor). Family Mustelidae (Weasels) (family / genus page) There are several mustelid species in Minnesota. Over half of members of Carnivora in Minnesota are mustelids. The family itself is also widespread. Many of the species that are present in Minnesota have a circumpolar distribution—or at least are distributed from eastern Canada to Alaska.
Mustelids have only 2 lower molars and 1 upper molar. The auditory bullae are flattened, and the skull is somewhat elongate. They have relatively short legs. In most species males are much larger than females. Family Procyonidae (Raccoon family) (family / genus page) . The procyonids are found in North and South America, and Asia (The lesser panda (Ailurus fulgens). Some have placed the lesser panda in a separate family. Minnesota has only 1 representative, the raccoon. Family Ursidae (Bear family) (family / genus page) . Bears are among the larger mammals in Minnesota. The tooth formula is 3/3, 1/1, 4/4, 2/3 x 2 = 42, but the first 3 premolars may be lost in adults. The only extant species in Minnesota is the black bear (Ursus americanus). Order Chiroptera (Bats) A distinguishing characteristic of members of the order Chiroptera, or bats, is that they fly and they all have wings. Minnesota Chiropterans are approximately mouse-size or smaller. Bats are generally slower fliers than birds, and all bats in Minnesota are nocturnal. An interesting feature of bats that we will look at in lecture is that they are heterothermic, dropping their body temperatures during the day while roosting. Many northern bats also hibernate.
Bats live longer than other mammals that are about the same size. Bats in Minnesota can live more than 20 years. Other characteristics that set bats apart from other small mammals are the long gestation period (about 60 days after fertilization) and the low reproductive rate (usually a single offspring a year). Family Vespertilionidae (Vespertilionids) (family / genus page) The Vespertilionidae is the only family of bats in Minnesota. Minnesota bats all hibernate, use echolocation to navigate, and eat insects. These bat species also use delayed fertilization, with mating occurring in the fall but fertilization delayed until spring after hibernation. The characteristic of bats that affect most people (attitudes and actions), other than their consumption of insects, is that bats are occasionally vectors of rabies.
In looking at the different bats, compare the teeth (when skulls are available), the hair color patterns, and the presence of hair on the uropatagium (interfemoral membrane), in addition to the animal’s size. Another physical characteristic that is referred to is the tragus, which is a projection from the lower margin of the pinnae (ear). Order Didelphimorphia (Opossums) Order Insectivora (Insectivores) Insectivora. Minnesota members of the order Insectivora are mouse-size or smaller, with pointed snouts, small eyes, and small or absent pinna (earlobe). Family Soricidae (Shrew family) (family / genus page) Members of the shrew family, Soricidae, do not have a zygomatic arch, have short ears which appear hidden by fur, eyes that are visible but smaller, and relatively small size. There are 6 species in Minnesota, some common, some rare. Teeth are reddish-brown at the tips in all Minnesota (and North American) species of soricids. Family Talpidae (Mole family) (family / genus page) Moles have a stouter, stronger appearing body than shrews. They have no external ears (pinna), reduced eyes, and strong front feet with broad palms. Order Lagomorpha (Rabbits, hares, and pikas) There are only 2 extant families in this order, and only one of these families, the Leporidae, occur in Minnesota. Lagomorphs have evergrowing incisors, we have already seen the peg-like second incisors directly behind the first pair of incisors that all lagomorphs (and no rodents) have. Also note the fenestration (holes) in the facial area of the maxilla, and also sometimes on the back of the head as well. Family Leporidae (family / genus page) The family Leporidae includes the rabbits and the hares. They have long hind limbs, long ears, and short tails. In most species females are slightly larger than males. The tooth formula for Minnesota leporids is 2/1, 0/0, 3/2, 3/3 x 2 = 28. A difference between rabbits (such as the domestic rabbit and the cottontail rabbit (Sylvilagus floridanus)) and hares (the genus Lepus) is that hare newborns are born with fur, with eyes open, and able to move around. In Sylvilagus and Oryctalagos young are born without fur, blind, and unable to move around. Order Rodentia (Rodents) . Rodents are the largest order of mammals, there are more rodent species in Minnesota than there are species in any other order. One family of rodents (Muridae) has more species than any other order in Minnesota. This pattern is similar to that in Mammals as whole, rodents represent about 40% of mammalian species.
Upper and lower jaws of rodents each have a single pair of evergrowing incisors, with no 2nd or 3rd incisors, or canines. There is a lengthened rostrum, and a diastema between cheeek teeth and incisors. Tooth formula is up to 1/1 0/0 2/1 3/3 x 2 = 22, although many species have fewer cheek teeth.
Couplet 2 of the Rodentia species key asks about the infraorbital foramen. The difference and the location to look for the infraorbital foramen can be seen in the images below. In Geomys bursarius the infraorbital foramen is visible from the side, in Sciurus carolinensis it is not visible. Family Castoridae (Beaver) (family / genus page) This is the beaver family, the only Minnesota representative is the beaver. Family Erethizontidae (Porcupine) (family / genus page) The only member of this family in Minnesota is the Porcupine. Family Geomyidae (Pocket gopher) (family / genus page) There are two species of pocket gophers in Minnesota, neither species is present in the Duluth area. Family Heteromyidae (Pocket mice) (family / genus page) The plains pocket mouse is the only member of the pocket mice and kangaroo rat family in Minnesota. Family Muridae (Mouse) (family / genus page) Muridae is a family with many species in Minnesota, in part because the family includes several species that were originally placed in separate families. The genera Reithrodontomys, Peromyscus, Onychomys, Clethrionomys, Phenacomys, Microtus, Ondatra, and Synaptomys all used to be placed in the family Cricetidae. This family is composed of mice, rats, voles, and lemmings. The traditional classification was to place many of the Minnesota species that are in Muridae (the old world mice) into a separate family called the Cricetidae (New world mice and voles). Currently, what were the cricetids are now placed in the family Muridae. Another family according to some taxonomists (Arvicolidae) is also now included in the Muridae.
This lumping of the up to 3 separate families results in a single family occuring in all faunal regions except for the Australian Region and some other areas in Asia. Part of this widespread distribution is due to the inclusion of Cricetidae into Muridae.
Tooth formula for all members of Muridae is 1/1 0/0 0/0 3/3 = 16 so that is not a distinguishing characteristic among species. One characteristic that can be used is the presence of grooves on the front of the incisors. The tooth formula can also be used to distinguish between members of Muridae and pocket mice (Heteromyidae) which have a premolar so the formula is 1/1, 0/0, 1/1, 3/3 x 2 = 20.
Within the Muridae there are three subfamilies: FIGURE OUT WHAT TO SAY HERE Family Sciuridae (Squirrel family) (family / genus page) : There are several sciurid, or squirrel, species in Minnesota. Tree squirrels include the common gray and fox squirrels, the red squirrel, the flying squirrels. Ground squirrels include woodchuck and other ground squirrels. |
