Prairies and savannas are both grasslands, but prairies have fewer trees. Savannas feature scattered trees, often oaks. These habitats often blend together. Illinois' prairies formed after glaciers shaped the land, with tallgrass prairies once covering much of the state. Rich prairie soil led to most prairies being converted to farmland. Today, few native prairies remain. Globally, grasslands make up 20 to 40% of Earth’s land and are called a few different names.

Muskrats are social aquatic rodents often mistaken for beavers or otters. They have long, scaly tails that act as rudders, webbed feet, and waterproof fur. Smaller than beavers, they build lodges or burrows near water and can swim up to 3 mph. Male muskrats use a musky odor from their scent glands to communicate and to warn intruders. They splash their tails to warn of danger and have adapted to live in the water. Muskrats are omnivores and prefer marshes and wetland habitats

Northern short-tailed shrews are secretive, underground insectivores often mistaken for mice, though they aren’t rodents. They have poor vision and use echolocation to navigate. Surprisingly, they are the only venomous mammal in the U.S.—their saliva can paralyze or kill prey. They feed mostly on invertebrates but also eat small animals and some plants.

Scales protect animals, but they vary by species. Reptile and bird scales are keratin-based and form a continuous layer. Fish scales, made of dentin and enamel, are made up of individual scales and come in four types: placoid, cosmoid, ganoid, and elasmoid. Each of these scales can help scientists determine valuable information such as a fish’s age and illnesses. Scale size and type affect locomotion and protection. You can view live examples at Four Rivers' large fish tank.

The world is home to 40 wildcat species, but only one, the bobcat, lives in Illinois. They are more prevalent in the southern part of the state. Bobcats prefer forested areas with a dense understory that are near open areas where they can hunt. A bobcat’s fur’s color helps them blend in with their habitat. They can look similar to domesticated cats and are commonly mistaken for lynx. Bobcats can run up to 30 mph during short sprints and are great stalkers. They often live sol

Boreal chorus frogs are one of the first signs of spring, often heard calling near ponds as early as February. Males sing to attract mates, and females lay up to 1,500 eggs. These small frogs, only 0.7 to 1.2 inches long, live in shallow, still waters. They are green or tan with three stripes down their backs. With short legs, they can only make small hops on land.

Fox and gray squirrels are common in Illinois and look alike, but fox squirrels have reddish-brown fur and are slightly larger, while gray squirrels have gray backs and white bellies. Gray squirrels prefer dense forests while fox squirrels prefer open woods. Other Illinois squirrels include red squirrels and southern flying squirrels. Black and white squirrels aren’t separate species. They get their unique color from genetic mutations like melanism, leucism, or albinism.

Redspotted sunfish, often called stumpknockers, come from a large family and are small freshwater fish with orange (males) or yellowish-brown spots (females). They prefer calm, plant-filled river backwaters. However, pollution, habitat loss, and invasive species led to their decline in Illinois, making them a state endangered species by 2009. Conservation efforts have helped - over 17,000 have been reintroduced, improving their status to threatened.