There are eight species of bats found in
Connecticut, but the two most common are the Little 
Brown and Big Brown bats. The six-remaining species (Silver-haired, Red, Hoary, Indiana, Eastern Long-eared and Eastern Pipistrelle) are less common and seldom, if ever seen. 

Known to survive for up to 19 years in the wild, most brown bats die in their first winter if they do not store enough fat to make it through their entire hibernation period.

Bats are the only mammals capable of actual flight. They are furred, warm-blooded mammals with wingspans ranging from a few inches to several feet. The bones in a bat’s wing are like those in human arms and hands. The fingers are extended and connected by leathery, elastic skin that grows from the sides of a bat’s body. Their thumbs are free from the wing membrane and have claws for grasping. They also have a very long tongue that they use for eating, drinking, and pollination. They can roll that tongue up around their rib cage too, when not using it.

Bats have good eyesight for low-light conditions and rely on vision for long-distance
orientation. For short-distance navigation and especially for catching food at night, they use
echolocation, which means they send out sound waves from their mouths and can pinpoint exactly where objects are based on the echoes that bounce back. Like dolphins, this sonar system is above the range of human hearing, and helps bats locate targets and background objects from the echoes resulting from emitted ultrasonic sounds. These ultrasonic sounds bounce back slowly when a bat is foraging and quicken as the bat pursues and captures an insect. Detection, pursuit and capture of an insect take about one second.
In addition to echolocation calls, bats communicate audibly with chirps and calls. These chattering sounds can be heard with the human ear when standing near a bat roost in the late afternoon, when they are getting ready to go out to forage.

Connecticut’s bats are primarily insect eaters. They are mostly nocturnal and almost always feed "on the wing". They use their wings, the skin around their tails and their mouths to catch insects in flight. Bats are the only major predators of night-flying insects, making them beneficial to human beings. Mosquitoes and other pests are eliminated much more efficiently by bats than by birds or expensive bug zappers. Insect-eating bats help reduce insect-borne diseases like West Nile virus. 

In general, bats are not dangerous, but they can carry rabies, although less than one percent of all bats are infected with the virus. More people die annually from dog attacks, bee stings, lightning and household accidents than from bat-transmitted rabies. That said, rabies is a dangerous and fatal disease and that is why it is vital that bats are never touched bare-handed. Bats have razor sharp teeth and their bites can be imperceptible, which is why health and safety
protocols mandate that a bat must be euthanized and tested for rabies if found inside a house (or handled) and a bite cannot be ruled out.

Bats find shelter in caves, crevices, tree cavities, buildings, and under bridges. Some bats prefer living alone, while other species reside in colonies. To survive the winter, some species of bats migrate, others hibernate, and yet others go into torpor (i.e., regulated hypothermia that can last from a few hours to a few months).

Mating season for bats in New England (temperate climate), is in the fall, and gestation generally lasts about 40 days for most smaller species. The pups, born in the spring, when there is plenty of food available, weigh up to a third of the mother’s body weight. Most female bats have a single pup once a year (Red bats may have as many as 2-4), and the mothers form maternity colonies where females roost together, keeping their babies warm and offering protection with strength in numbers.

Bats roost upside down since the lightweight bones in their hind legs cannot support their body weight in an upright position. Their wings wrap around them like a cloak while they rest. Bats sleep during the day and go out at night (usually at dusk) in search of food. Bat wings are laden with blood vessels, which help them heal rapidly if injured. Most bats take off by dropping from a hanging position, in a “swooping” fashion. This is why when bats are grounded, they can’t fly off but instead become stuck on the ground. Bats land by slowing down until they stall and grabbing hold of a branch or other surface. Some bats perform a flip and then grab hold!

A mother gives birth while hanging by her feet; she must catch her baby with her wings as s/he drops! For the first days, the baby bat will cling to the mother bat. A mother bat can locate her pup by its scent and sound even though many pups may be present in a colony. 

Most young begin foraging with their mothers sometime in July, but they may not be independent until the end of the summer. The newborn of some species cling to the mother while she hunts, but most offspring are left behind because they quickly become too heavy to be carried. Bats often use attics as nurseries, because they maintain desired temperatures for raising young. Nursery
colonies only contain breeding females and their young, as the adult males and non-breeding females roost elsewhere.
The pup is born without hair and with its eyes closed. The mother nurses her pup for two to six months, then teaches the baby to fly and find food. The pup can cling to the mother with sharp claws while she roosts, or s/he can hang alone. With rare exceptions, the father does not normally participate in helping raise the baby. A bat pup learns to fly within three to six weeks of birth, depending on the species.

Bats across the eastern US and Canada have fallen prey to a fungal infection called White-Nose Syndrome. The fungus appears as white patches on the muzzles, wings, ears and other exposed skin tissues of hibernating bats, but not all bats exhibit this symptom. Infected bats sometimes emerge prematurely from torpor or hibernation, flying during daytime in winter for example. The abnormal behavior associated with this disease is thought to contribute to the premature consumption of fat reserves resulting in emaciation and death.
(hairless or grounded)

(grounded, injured or sick)