Bats: Ecology, Conservation and Myths
Bats are the only mammals with true, powered flight. Unlike the gliding flight of flying squirrels and lemurs, bats use their wings for active flight. Like other mammals, bats are warm blooded (endothermic), covered in fur and feed their newborn offspring with milk.
There is a huge diversity of bat species worldwide, with up to 1,400 known species and new species being found every year, such as the orangutan-hued bat, Myotis nimbaensis, which was found in the Nimba Mountains in Guinea just last year. Bats range greatly in size, with flying foxes reaching a wingspan of two metres and a weight of 1.5 kilograms, while the tiny bumblebee bat has a wingspan of only 15cm and a weight of two grams, making it the smallest mammal in the world. Bats have a wide range of feeding habits, with different species specialising on insects, fruit, fish, blood, nectar and even frogs. Some bats use echolocation to find food while others use their strong sense of smell and also sight.
Bats also experience full hibernation over the winter, which is a state of inactivity that allows them to survive long periods of time without food. This involves having a much slower heart rate, metabolic rate and rate of breathing. Bats tend to begin hibernating in October and come back out in April. Female bats will then form maternity colonies to find a suitable nursery site where they will each give birth to a single pup in May and June. After three weeks, these pups will begin to learn to fly and after six weeks, they will be able to catch insects for themselves. At this point (August-September), the maternity colonies will disperse and the bats will begin to search for a mate while also increasing their fat stores for the winter. In October, they will locate a new hibernation site where they will spend the winter.
The largest diversity of bats is found in warmer, equatorial regions, with one third of all species being found in Central and South America. However, we still have several species here in Ireland. All of Ireland’s bats are insectivores, meaning they specialise only in eating insects. They each prefer different habitats, such as near rivers, woodlands or grasslands.
There are nine confirmed bat species in Ireland, belonging to two separate groups:
- Family Vespertilionidae
- Common pipistrelle (Pipistrellus pipistrellus)
- Soprano pipistrelle (Pipistrellus pygmaeus)
- Nathusius’ pipistrelle (Pipistrellus nathusii)
- Leisler’s bat (Nyctalus leisleri)
- Brown long-eared bat (Plecotus auritus)
- Daubenton’s bat (Myotis daubentonii)
- Whiskered bat (Myotis mystacinus)
- Natterer’s bat (Myotis nattereri)#
- Family Rhinolophidae
- Lesser horseshoe bat (Rhinolophus hipposideros)
Threats and Conservation
Bats play an important role in an ecosystem through pollination and seed dispersal and they are also an indicator species for habitat health. Many plant species are pollinated by bats, such as mango, banana and agave. As bats are predators of nocturnal insects, high diversity in bat populations is a good indicator of a healthy habitat and can aid in pest control.
Threats to bats include a shortage of their insect prey, due to pesticides used in intensive agriculture and habitat loss. The loss of old buildings and felling of old deciduous trees also reduces availability of roost sites for bats. Similarly, chemical treatments placed on timber beams in roofing can be toxic to bats. It has also been suggested that the use of the antiparasitic drug Ivermectin used in cattle can reduce beetle numbers which may affect bat foraging behaviour and conservation (Finch et al., 2020). However, on a more positive note, it is thought that the recent expansion of the great spotted woodpecker in Ireland might increase availability of roost sites for bats (Kotowska et al., 2020).
Ireland’s bats are all protected under the Wildlife Act (1976) and the Wildlife (Amendment) Act 2000. Bat’s are also a European protected species under Annex IV of the European Habitats Directive. It is an offence to intentionally harm a bat or disturb its resting place.
Bats are often feared and misunderstood which has led to many myths surrounding them:
“Bats are blind” All bats can see. Some species have better eyesight than others, primarily species that do not rely on echolocation, as they often hunt for food with sight and smell alone.
“Bats suck blood” Vampire bats do exist in Central and South America where they have been recorded feeding on livestock, such as cows, pigs and chickens. However, despite how they appear in horror movies, vampire bats have rarely been recorded feeding on humans. Regardless, all Irish bats feed solely on insects and do not drink blood.
“Bats will get caught in your hair” Definitely not! Their keen echolocation allows them to know exactly what is around them and so they will not get stuck in your hair. This myth stems from bats swooping down to catch insects above people’s heads.
“Bats are just flying mice” Bats are actually more closely related to primates, such as humans, than they are to rodents!
“All bats have rabies” There have never been any bats found with rabies in Ireland, although a very small proportion have been found in the UK and other countries in Europe. For this reason, it is important to always wear gloves when handling bats and other mammal species, as they do have the potential to carry rabies and it can be transmitted through bites and scratches.
If you have found a grounded bat during the day, never handle it with bare hands as it may bite. Try to ensure it is in a safe, warm place and provide food such as mealworms or chopped up cat and dog food. You can also provide water in a small, shallow dish. Once the bat is safe, you can get further advice from Bat Conservation Ireland or Irish Wildlife Matters or contact the National Parks and Wildlife Service in the Republic of Ireland on (01) 888 2000.
Bat Conservation Ireland https://www.batconservationireland.org/irish-bats
Bat Conservation Trust UK https://www.bats.org.uk/
Finch, D., Schofield, H., Floate, K.D., Kubasiewicz, L.M. and Mathews, F. (2020), Implications of Endectocide Residues on the Survival of Aphodiine Dung Beetles: A Meta-Analysis. Environ Toxicol Chem, 39: 863-872. https://doi.org/10.1002/etc.4671
Kotowska D, Zegarek M, Osojca G, Satory A, Pärt T, Żmihorski M. Spatial patterns of bat diversity overlap with woodpecker abundance. PeerJ. 2020 Jun 18;8:e9385. doi: 10.7717/peerj.9385. PMID: 32596056; PMCID: PMC7306217.
Written by Rebecca O’Sullivan