Recently, my friend Charlie Fox mentioned that a mouse had crossed the road in front of his vehicle. What was strange was that the mouse jumped like a kangaroo.
Charlie questioned whether we have kangaroo mice here in Pennsylvania. Since I was asked the same question many years ago, I knew the answer.
No, we don't have kangaroo mice here in Pennsylvania; however, we do have two species of mice, which can and do on occasion jump like a kangaroo.
One is the meadow jumping mouse, which is adapted for jumping and often referred to as a kangaroo mouse; however, that's as far as the relationship goes.
The usual gait of the jumping mouse is a normal four-legged scamper but if either frightened or in a hurry, the mouse takes off in high arching leaps that could propel it from 6 to 8 feet. Although the leaps give the mouse amazing speed, one great disadvantage is that the mouse cannot choose its landing place and often falls into holes, ditches, etc.
These jumping meadow mice, which primarily are seed eaters, do not store their food. The meadow jumping mouse and its close relative, the woodland jumping mouse, are Pennsylvania's only hibernating mice.
Just as bears store up fat, jumping mice also store up an enormous amount of fat each fall and, by October, the mice will have entered into their long winter's sleep. Their body temperature drops, circulation slows down and breathing is slight compared to their 145 breaths per minute during the summer months.
They remain in hibernation until the end of April. The exact dates of hibernation are not set by day-to-day weather conditions but by the readiness of the animal. The jumping mice seen out and about later than normal are those that have not put on enough fat to go into hibernation.
In one book, I read that many jumping mice do not survive the torpor state because of insufficient fat reserves.
Young are born in nests below ground. The nests usually are lined with grasses. A gestation period is about 18 days. An average litter size is five to eight, and the female usually has two litters per year.
The young are born hairless and blind, with their eyes opening at two weeks. The young will nurse about 28 days and, shortly after weaning, the young disperse, and a second litter will be born.
Some young in the first litter will breed during that first summer; however, those of the second litter do not breed until the following spring.
A full-grown jumping mouse will measure 8 to 9 inches in length, with 5 to 6 inches of this the tail.
At night, owls and. by day, snakes, weasels, foxes, bobcats, minks and hawks feed upon jumping mice. Their kangaroo leaps help in escaping; however, the fact that the mice are unavailable during their hibernation is the main reason they exist. In the wild, their average life span is less than one year.
The habitats for the meadow jumping mouse and the woodland jumping mouse are indicative of their names.
Although the two species are colored similarly, the woodland jumping mouse is lighter in color. The main field identification is a white-tipped tail in the woodland jumping mouse and a brown-tipped tail for the meadow jumping mouse. Also, the woodland jumping mouse is larger than the meadow jumping mouse.
The mice are most active at night but can be seen during the day, especially on either a cloudy or rainy day. The meadow jumping mouse is found throughout the state, while the woodland jumping mouse is more common in the northern counties but absent from the southcentral and southeastern section of the state.
The population of both species varies from year to year. In some years, the mice seem to be everywhere and uncommon during the next year.
I believe that Charlie saw a meadow jumping mouse since there were fields on both sides of the road where he saw it.
I feel cheated that I have never seen either of these jumping mice. Seeing one probably was as exciting as seeing a bear, big buck or bobcat. Charlie certainly was excited.
Bower retired after 34 years as a wildlife conservation officer for the state Game Commission. He has published several books about his experiences. Questions and comments may be sent to him at 153 Redington Ave., Troy PA 16947.