Montshire Minute: Enchanted Forest 2004

Originally aired during the week of September 27, 2004

Monday

Who knows what creatures cavort in Montshire's woods around Halloween? You can find out Saturday evening 23 when the Museum becomes... an enchanted forest! You'll have a chance to explore our trails at night (led by one of our expert guides, of course) and meet many native nocturnal animals in fun and surprising guises. If you are observant, one creature you are sure to see in the twilight hours is the common brown bat. You might see it flitting above a field or pond, swooping close to a tree or maybe close to you - before it swerves away. Despite their sinister reputation, bats are actually performing a great service. Their nighttime activity consists mostly of eating insects like midges, mosquitoes and mayflies. According to the Vermont Fish & Wildlife Department, 50 bats can eat up to 30 million insects in one summer. Now that's pest control!

Tuesday

There are nine different species of bats that live in Vermont and New Hampshire. By far the most common is the little brown bat, which mates at about this time of year. The sperm remains in the female's reproductive tract until spring, when the eggs are fertilized. Around April and May, expectant mother bats join together in "nursery" colonies, often in houses or other structures, where hundreds may gather to share their warmth and raise their young. Mother bats help each other with rearing the babies, and, amazingly enough, each female recognizes her own offspring among the many of babies on the roost wall. As the mothers return from feeding, each baby recognizes its mother's voice, rears up, and calls to signal its location. They even have a mechanism to prevent themselves from hearing their own cry so that it doesn't interfere with the echoes.

Wednesday

Most bats raise just one youngster per year, and the mother is very attentive to its offspring. The first few days after the baby is born, the mother suckles it constantly, except when foraging for food. According to the National Audubon Society Guide to North American Animals, the young remain in the roost for about four weeks. They will begin to fly at 18 days of age, and after three weeks they have reached their full adult size. Male bats hunt for insects at night and roost alone in trees during the day. During the summer, brown bats may roost in the attics of houses - they can withstand temperatures of up to 61 degrees Celsius, or 140 degrees Fahrenheit. Before winter sets in, little brown bats leave their nursery colonies and hibernate in mines or caves.

Thursday

In the fall, little brown bats will sometimes fly hundreds of miles to find the right conditions for winter hibernation. Often they will gather in a mine or cave. Roosts chosen for hibernation usually have a constant temperature of around two degrees Celsius and a very high level of humidity. The brown bat is a true hibernator - its body temperature drops and its heart rate slows to conserve energy. Still, the bat may wake up on an average of once every two weeks during hibernation, and may even take flight on a warm winter evening. You can find out more about bats and other nighttime denizens of the woods by taking part in the Museum's Enchanted Forest program on Saturday evening, October 23. You'll meet many native nocturnal animals in fun and surprising guises!

Friday

How do bats avoid bumping into things at night? A bat guides itself through the dark by locating the echo of its own squeaks. This is called echolocation. Human ears can detect a range of sixteen to thirty thousand vibrations per second. Bats can hear from thirty thousand to seventy thousand vibrations per second. So, bats broadcast a high vibration of squeaks and detect the interval of time it takes for the echo to return to their ears. As a bat approaches an object the echo returns to its ears more quickly than if the object were farther away. The high frequency of the squeaks paired with the very sensitive auditory system of the bat allows the nocturnal flyer to hunt tiny insects and avoid obstacles with amazing accuracy. In fact they can detect objects as fine as human hair.