Going Batty for Bats

 

Going Batty for Bats

Written by Kristine Manganelli (Somerset County 4-H Coordinator)

Colony of Bats

Colony of Bats

I don’t know about you, but I’ve been getting A LOT of mosquito bites lately! Although being itchy is part of the summer experience, I find myself wondering about the purpose of these little pests. With this blog I hope to remind you that there is ALWAYS a purpose, even for the smallest, most annoying of critters.

Don’t worry, this is not a blog post praising the mighty mosquito, but a post to put in perspective, the role that each life form plays in nature. You might notice that mosquitoes often come out to feed at dusk, and if you observe carefully during this time, you may spot a bird flying nearby. Upon closer inspection it seems like this bird is flying a bit erratically, and the wings don’t look quite right. It isn’t a bird, it’s a bat!

Mosquito’s are a major food source in both their adult and larval stages for many creatures such as birds, dragonflies, and bats. Many may view the bat as pests themselves for their creepy Halloween vibes, their habit of making homes in attics, and their reputation for rabies. So ugly they are cute, bats have much more to offer than these stereotypes describe.

Bats are found around the world, with fossil records dating back 50 million years. Scientists are still unsure of their evolution from terrestrial dwellers to flying mammals, but theorize that they started out gliding from tree to tree.

New Jersey is home to 6 year-round bat species (big brown bats, little brown bats, eastern small-footed bat, tri-colored bat, northern long-eared bat, Indiana bat), and 3 migrating species that travel south for the winter (hoary bat, eastern red bat, silver-haired bat). The bat species here are insectivorous and are one of the only major predators of nighttime insects.

Bat species in warmer climates are critical to the pollination of flowers for some of our favorite foods like bananas, avocados, cashews, and mangoes. Their role in seed dispersal helps to restore tropical rain forests that have been disturbed by logging or fires.

In New Jersey they can be found foraging in areas with high insect populations such as the edge of woodlands, near bodies of water, and around lights. Bats consume up to half of their body weight in bugs each night, and twice that amount when pregnant or nursing. A single bat can eat up to 1,200 insects per hour, and thousands per night. A colony of bats can consume millions of insects each year. In addition to mosquitos, bats eat many types of insects including gypsy moths that devastate our forests, and agricultural crop pests. This actually reduces the need for chemical pesticides, saving the United States billions of dollars each year.

Bats are the only mammals capable of true flight from the order Chiroptera, which is Latin for "hand-wing." As mammals, their wings are similar to the human arm. Like us, bats have upper arms, forearms, wrists, hands with four fingers, and thumb. They use their clawed thumbs to cling onto surfaces (You can view this thumb in below photo sticking up from folded wing). The wing structure is composed of two layers of skin membrane stretched between the fingers, legs, tail, and along the length of the arms.

Bats are nocturnal, meaning they are active at night, a behavior likely evolved to avoid predators of the day. Although they do rely on echolocation for hunting and navigation, bats are not blind and their eyes are adapted to see in the dark. They also have a strong sense of hearing, which aids in the process of echolocation. Bats emit ultrasonic pulses into the air that bounce off nearby objects and back to the bat’s ears. Based on the timing of returning pulses, bats are able to determine their surroundings with enough accuracy to pinpoint tiny insects. This makes their flight patterns seem random, but each of these movements are intentional.

In the winter when food sources are scarce, New Jersey bats hibernate in caves or abandoned mines. During this time they enter a state of torpor where an extremely low heart rate, metabolism, and body temperature allows them to conserve energy and survive the season without food.

As the weather warms and insects return, they move to trees or dark structures like chimneys and attics where they sleep during the day. Males usually roost alone, while females roost in “maternity colonies” where they give birth and raise their young. They usually have one pup, and like other mammals, babies are totally reliant on mom for warmth and milk. The pups are fully grown and can feed independently by 4-5 weeks.

As people prefer not to have bats in their homes, be sure to seal any small openings they may be able to enter. If they do get inside, it is important to know that they are not aggressive and can be responsibly removed by trapping in a room and leaving a window open. If this is not possible, please call your local animal control. Although bats can be infected with rabies, it is only transmitted through a bite which is an extremely rare occurrence. On top of that, less than one half of 1% of bats have rabies in the wild.

Little Brown Bat from NJ Bat Sanctuary

Little Brown Bat from NJ Bat Sanctuary

Since its origin in a cave in Albany, New York in 2006, some bat species have suffered due to a disease called White Nose Syndrome, responsible for killing millions of bats across the Eastern United States. This is caused by a fungus that effects hibernating bats when their immune systems are suspended. It displays as a white powder on the face, ears, and wings.

White Nose Syndrome weakens the bat’s immune system, causes dehydration and tears in the wings that impact flight and regulation of systems like body temperature and blood pressure. It can also cause them to wake too soon from hibernation and starve to death from lack of food during the winter season.

White Nose Syndrome arrived in this area in 2009, and has since killed tens of thousands of bats in New Jersey. Little brown bats are most susceptible due to their preference for hibernating deep in caves where warmer temperatures support the fungus, while big brown bats stay closer to the cave entrance. In fact, 98% of the little brown bat species in New Jersey has been wiped out.

Researchers at Rutgers University have found that little brown bats have shifted their behavior to hibernate closer to the entrance where temperatures are cooler. Although the population increases slightly each year, it is likely that the numbers will never return to normal. This disease could make cave-dwelling bats candidates as future endangered species.

In addition to disease, humans are also problematic for bat populations. Irresponsible use of pesticides not only damage bats themselves, they also decimate the insect population on which they feed. Deforestation and removal of dead trees reduces bat habitat, and water pollution can negatively impact insects in larval stages.

A world without bats would mean millions of additional insects out there harming ecosystems, crops, and irritating people. It is estimated that each year over 60 tons of mosquitoes and other night-flying insects remain due to bat population decline. See below for ways to protect bats so they can keep our insect population at a healthy level.

What You Can Do to Help:

 
Somerset County 4-H