Bats have been around for at least 50 million years and in that time have evolved to take advantage of a great variety of habitats. The more than 1,000 species live on all continents except Antarctica and occur everywhere except in polar regions and in extreme deserts. They range from the very tiny, weighing less than a penny, to giants with wingspans over 6 feet.

Bats come in many colors: black, white, yellow, brown, orange, red, and blue-gray. Bats are mammals and have adapted almost every mammalian feeding strategy. Some are carnivores and hunt small rodents, birds, lizards, and frogs. Some are even fishermen. Some bats are herbivores and feed on plant nectar and fruit. Other bats are insectivores and play a large part in keeping insect numbers in check. And some bats are parasites; these are the vampires that survive by feeding on blood from other animals.  (The vampire bats don’t suck blood, they make a small incision and lap  up the blood.)

Bats are important pollinators for a variety of plants including the saguaro and other cacti. The fruit eaters help disperse the seeds.

Bats can fly, maneuver, and locate insects in complete darkness due to their acute hearing and practice of echolocation. Bats emit a sound, mostly in frequencies higher than human ears can detect. That sound bounces off objects and prey, and returns to the bat. The bats judge distant by the time delay of the returning sound.

Bats are not blind. Bat’s eyes contain rod photo-receptors for night vision and cone photo-receptors for daylight and color vision. They can see into the ultraviolet which helps them maneuver in twilight and better recognize UV-reflecting flowers during the day.

Bats live in crevices and caves, mines, under bridges, in attics or barns. Some bats hibernate, others migrate. I have a family of bats living somewhere near my house. At dusk on summer evenings, they come out and drink, on the fly, from my pool.

Bats, like other mammals, can carry rabies which is fatal to humans. The virus is transmitted by a bite. According to the CDC, it can also be transmitted when the saliva from a rabid animal comes in contact with a person’s mouth, eyes, nose, or a fresh wound. Some studies indicate that about 5% of the bat population carry rabies. Histoplasmosis, a fungus associated with bird and bat droppings, can become airborne and inhaled. Most infections are mild and produce either no symptoms or a minor influenza-like illness. On occasion, the disease can cause high fever, blood abnormalities, pneumonia and even death. The CDC says that “research suggests that bats might be the source of several hemorrhagic fevers, which affect multiple organ systems in the body and often lead to life-threatening diseases.” They also found bats carrying the deadly Marburg virus. Bats suspected of carrying these diseases live in Africa.

Bats, themselves, are subject to disease. Recently “white nose syndrome” has killed millions of bats mainly in the northeast U.S. This disease is suspected to be a fungus.

There are many places to observe bats around Tucson such as Saturday summer nights at the Arizona-Sonora Desert Museum. Other good places around Tucson include the East Broadway bridge over the Pantano Wash, the North Campbell Avenue bridge over the Rillito, and the East Tanque Verde bridge over the Rillito.

You can find photos and fact sheets on several bats of the Sonoran Desert here. 

At Bat Conservation International you can find information on building bat houses and on how to safely and humanely remove a bat from your house.

See also:

Creatures of the Night: Kangaroo Rat

Creatures of the Night: Grasshopper Mouse

Who’s Afraid of Tarantulas?

Who is Tyto Alba? = Barn Owl

Western Screech Owl

Rattlesnakes

Speckled Rattlesnakes

Scorpions, Vinegaroons, and Sun Spiders

Mice will eat just about anything, but most prefer plant parts. The grasshopper mouse, however, is a ferocious carnivore. It eats grasshoppers, beetles, spiders, centipedes, millipedes, worms, lizards, scorpions, snakes, and other mice. It hunts like a cat and defends its territory by howling – it is the mouse that roars.

There are several species and most inhabit the grasslands of the great plains, but at least one species is a desert dweller. The Northern Grasshopper mouse has a range from Canada to Mexico, and California to Minnesota; the Southern Grasshopper mouse has a range that includes parts of Nevada, Arizona, New Mexico, and Texas. The southern species is gray-brown- to cinnamon colored with a short white-stripped tail. Most grasshopper mice are relatively stout compared to other mice. The head and body is 3.5″- to 5″ and the tail is 1″ to 2.5″ long.

Usually a male-female pair live together and defend a territory. It marks the territory with musk.

Grasshopper mice have very strong jaw musculature required for killing prey. And they learn quickly how to deal with various prey. One observer describes how the mouse dealt with a 3-inch scorpion in Arizona: ” The mouse would first nip the tail so that the stinger was ineffective. It would then stand the scorpion on end, holding it with its front paws, and methodically eat the writhing creature head first.”

The grasshopper mouse is a nocturnal hunter, a good climber, and active year round. In some areas, scorpions account for almost their entire diet, which might be surprising because the mice are not known to have any immunity to scorpion venom.

These mice will eat seeds, grasses, and grains, and cache them, like other mice, but about 90% of their diet is animal matter. The strangest part of their diet is sand. Biologists think the mice eat sand to aid in digestion, just like some birds ingest gravel. And that’s not all that is strange about their digestive system. As described in an article by Mary Ingle: “A pouch attached to the underside of the stomach opens into it via an aperture too small for large food particles to pass through. The pouch contains all of the gastric glands that contribute to the breakdown of food and are normally found in the stomach of other mammals.” Ingle speculates that the pouch exists because the insect diet would be too rough and damaging for delicate gastric glands to function normally.

The grasshopper mouse digs four kinds of burrows: nesting, retreat/sleeping, caching, and the bathroom.

The mice have several vocalizations. You may have heard their territorial proclamation and mistaken the high-frequency sound for that of an insect. So now, when you are out at night, listen for the mouse that roars.

For a video of a battle between a grasshopper mouse and a very large centipede check here: http://tinyurl.com/ylyme9w Note that centipedes are venomous.