Some animals live underground for all or much of the time. Living underground has many advantages, including protection from some predators, from extreme temperatures (both hot and cold), and from overly dry climates. Many animals also hunt for food underground, like tubers, roots, other plant material, worms, grubs, insects, insect eggs and larvae.

Some animals, like moles and earthworms spend their entire lives underground. Others, like the prairie dog, spend some time below ground and some time above ground. Some animals spend a portion of their life cycle underground (for example, some insect larvae).

Fossorial means relating to burrowing or living underground. Fossorial animals are adapted to living underground. Aardvarks, armadillos, and moles are fossorial animals

Teeth of Carnivores 
Carnivores such as dogs or cats have long sharp teeth for stabbing and killing their prey. These long, 
sharp teeth are near the front of their mouths and are called canine teeth. In the back of their mouth 
are short, sharp teeth for grabbing and holding a struggling animal. Carnivores eat by taking large bites 
and swallowing chunks often without chewing their food. 
Some teeth can be easily distinguished by shape and/or placement in the mouth. Incisors (front-most 
teeth) in carnivores tend to be small and mostly used as a grooming tool since their mode of eating is to 
primarily bite off large chunks and swallow without a lot of chewing. Their canines (stabbing teeth) tend 
to be prominent and enlarged facilitating the holding and dispatching of prey. Premolars and molars are 
reduced in number and have sharp surfaces. 
Teeth of Herbivores 
Herbivores have wide, flat teeth (molars) in the back of their mouths for grinding grasses, seeds, leaves, 
bark, and other plants they eat. In the front of their mouths, they tend to have sharp, flat teeth for 
snipping off these plants. 
Rats and mice are herbivores and also rodents. One characteristic of rodents is that the incisors (frontmost teeth) are chisel-shaped, and ever-growing (continue to grow the animal’s entire life). The front of 
the incisor is made of a stronger material than the backside of the incisor, so as the animal chews, the 
back of the tooth wears down faster, adding to the chisel-shape. Also, many rodents have pigmented or 
colored incisors as is evident in the rat. 
In some herbivores, such as a deer, the upper incisors and the upper canines are missing. The lower 
canines are either extremely modified and reduced in size or missing altogether. Some herbivores will 
rely on their tongues to lick up leaves or grass then shear off the plant materials with their lower incisors 
only. Many herbivores have special stomachs so they can regurgitate the food from a special 
compartment in their stomach to continue chewing it at a later time. Extra compartments are needed in 
the stomach to help break down the tough cellulose in plant matter, especially for browsers, such as 
deer. 
Teeth of Omnivores 
Raccoons and skunks are examples of omnivores, meaning they will eat both plants and animals, 
including worms and insects. Teeth of omnivores are not as uniform in type as the teeth of carnivores 
and herbivores. In addiction, the canine teeth are less prominent and the molars are more flat than jagged. In fact, humans are omnivores as well.