Bats in Bermuda

Bats have earned a scary reputation because they are usually seen at night and we do not understand them, however they provide humans and the environment with many valuable services. For example, some plants are pollinated by bats and bats eat many of the bugs that destroy farmer's crops. 

Bats are mammals, just like dogs, cats and people. They are the only mammals in the world that can fly. Bats, like other mammals, have live babies which the mother feeds with milk. They are warm blooded and their bodies are covered with hair.

Bermuda has no native resident land mammals but four species of migratory North American bats visit occasionally: the Hoary Bat, Eastern Red Bat, Seminole Bat and Silver-haired Bat. These bats are usually found in Bermuda during their spring and fall migrations, from August to November and April to June. They are not thought to be resident here, just passing through.

Two other species of bat have also been recorded in Bermuda: the Big Brown Bat (Eptesicus fuscus) and the Eastern Pipistrelle (Pipistrellus subflavus). These last two species do not migrate south for the winter, instead they find a warm, dry place to hang up-side-down and hibernate (sleep for the winter). The single Big Brown Bat recorded in Bermuda arrived inside a shipping container in November 1989, so it was likely settling down to hibernate for the winter in the container before it was shipped. There have been several reported sightings of small bats in Bermuda which may have been the Eastern Pipistrelle, along with one that was brought to the Aquarium after being found roosting on a parked bike! [Wingate, 2005a]

Bats hunt for food between dusk and dawn, and go back to a favourite place to rest during the day (called roosting). The bats found in Bermuda are more likely to roost in trees than in caves. Bermuda does not have enough forest left to support a resident population of bats, and there is not sufficient food here to support many of them for long. All of the bats recorded in Bermuda eat insects, such as moths, flies, wasps, bees and crickets. They feed while flying around at night, so they produce sounds that bounce off flying insects and echo back to the bats, letting them know where the food is located. This is called echolocation.

Hoary Bat (Lasiurus cincereus)

The Hoary Bat is widespread in North America from Canada to Guatemala. This bat has long soft hairs on its back that are grey in young bats and brown in adults. The tips of the hairs are white, which gives it a frosted appearance and thus its name. The belly is darker brown, and there is also brown fur on the underside of the wings. Hoary Bats weigh 20-35 g (0.7-1.23 oz) and the average wingspan is 43 cm (16.9 inches). These bats are usually seen alone, but may join up with others to hunt. They are one of the only bats that make sounds while flying that humans can hear. 

Eastern Red Bat (Lasiurus borealis)

Red Bats are found from southern Canada to Chile and Argentina. They migrate to warmer parts of their range in the winter. The Red Bat is a medium sized bat weighing about 7-13 g (0.25 – 0.46 oz), and ranges in colour from brick red to yellowish red, with white tips on the hairs. The red colour helps them to blend in with dead leaves and branches when they are roosting in trees. The female has a set of twins each year, and nurses them until they learn to fly at about 5 weeks of age.

Silver-Haired Bat (Lasionycteris noctivagans)

This bat is found from southern Canada to the southern United States, mostly in temperate forests. Silver-Haired Bats are medium sized weighing 8-12g (0.28-0.42 oz), with a wingspan of 27-31cm (10.6 – 12.2 in). The Silver-Haired Bat usually has black fur with silvery white tips. They have 2 babies, which unlike human babies are born with most of their teeth. They are thought to live up to 12 years, and can be found on their own, in pairs or in small groups.

Seminole Bat (Lasiurus seminolus)

Seminole Bats are found in forests in the southern United States from North Carolina to the Gulf of Mexico and eastern Texas. They weigh 7-14g, (0.25 – 0.49 oz) with a wingspan of 10.8-11.4 cm (4.25 – 4.49 in), and look similar to Red Bats. The fur is reddish brown with white hair tips and a white chest and throat. They produce an average of 3 young which is high for bats. The babies can fly at 3-4 weeks of age. The Seminole Bat is solitary and active all year round at dawn and dusk if the temperature is above 20 degrees C (68 F).

Eastern Pipistrelle (Pipistrellus subflavus)

These bats are found in southern Canada, along the east coast of the United States and Mexico as far south as Honduras. They roost in trees, rock crevices and caves in the summer and hibernate in caves or mines in winter. This is a small bat weighing 4.6-7.9g (0.16 - 0.28oz) with a wingspan of 22-25 cm (8.7-9.8 in).  The hairs of its fur are dark at the base and the tip and yellowish brown in the middle. The Eastern Pipistrelle has a set of twins also, which is rare among bats. The babies grow their fur within a week and can fly after 3 weeks. They live 4-8 years. They begin hibernation between July and October and finish in early April. They hunt a variety of insects using echolocation, including beetles, flies, butterflies and bees.

Big Brown Bat  (Eptesicus fuscus)

The Big Brown Bat is found from southern Canada to northern South America and in the West Indies. It is a large bat weighing about 23 g (0.81oz or as much as 23 paper clips) with a wingspan of about 33 cm (13 inches). The fur on the back is darker than on the stomach. Usually the back is tan to dark brown and the underside is pinkish to olive. They can live up to 19 years in the wild. They hibernate in the winter in caves or buildings.

If you see a bat in Bermuda consider yourself lucky! Please report your sighting to the Natural History Museum at BAMZ. More information on Bermuda’s bats can be found in the following sources in the BAMZ library:

• Van Gelder RG, Wingate DB. 1961. The taxonomy and status of bats in Bermuda. American Museum Novitiates 2029 : 1–9.
• Wingate, D. B. 2005a. A new bat species for Bermuda. P. 42 in Bermuda Audubon Society. 50th anniversary 1954–2004 (A. Dobson, ed.). Bermuda Press, Hamilton, Bermuda.
• Wingate, D. B. 2005b. First record of the eastern pipistrelle bat,Pipistrellus subflavus, from Bermuda. Critter Talk [Bermuda Zoological Society] 28:16–7.

Information References:

• Anderson, S. 2002. "Lasiurus cinereus" (On-line), Animal Diversity Web. Accessed October 01, 2009.
• Myers, P. and J. Hatchett. 2000. "Lasiurus borealis" (On-line), Animal Diversity Web. Accessed October 01, 2009.
• Naumann, R. 1999. "Lasionycteris noctivagans" (On-line), Animal Diversity Web. Accessed October 01, 2009.
• Walker, T. 2002. "Lasiurus seminolus" (On-line), Animal Diversity Web. Accessed October 01, 2009.
• Hamlin, M. and P. Myers. 2004. "Pipistrellus subflavus" (On-line), Animal Diversity Web. Accessed October 01, 2009.
• Mulheisen, M. and K. Berry. 2000. "Eptesicus fuscus" (On-line), Animal Diversity Web. Accessed October 01, 2009.

Also see:

First winter record of Seminole Bat, by David Wingate in the Bermuda Audubon Society Newsletter, Vol. 18 #1. Fall 2007.