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Page:The Zoologist, 4th series, vol 3 (1899).djvu/501

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THE MODE IN WHICH BATS SECURE
THEIR PREY.

 

By Charles Oldham.

 

Observations made during the past few months have to a great extent confirmed my suggestion (ante, p. 51) that the method adopted by the Whiskered Bat (Myotis mystacinus) and the Long-eared Bat (Plecotus auritus) to secure their prey was common to other species. This curious habit seems to be little known, or, if noticed at all, to have been misunderstood,[1] and is so remarkable that a further description of it, even at the expense of repetition, will, I trust, be forgiven.

When walking, most of our British Bats carry the tail curved downward and forward beneath the body, the interfemoral membrane forming a pouch or bag. If a moth or other large insect be encountered, the Bat seizes it with a rapid snatch, slightly spreading its fore limbs with the wings still folded, and, pressing them firmly on the ground at the carpus in order to steady itself, brings its feet forward in order to increase the capacity of the pouch, into which, by bending its neck and thrusting its head beneath its body, it pushes its prey. If the moth be a large one the Bat often struggles convulsively for a few seconds before it can adjust its grip to its satisfaction; but once in the pouch the insect rarely escapes, and, when effectually secured, is brought out and eaten openly. If the Bat can be induced to feed whilst hanging head downwards, suspended by its toes, its actions can be observed much more easily. Its tactics are then more efficacious, as the tail is not pressed close to the belly, and the pouch is in consequence held open, as it would be, of course, during flight.

This habit, practised readily and frequently in captivity, is so perfect an adaptation of means to an end that it must obtain with equal frequency among Bats in a free state. These creatures,

  1. In Bell's 'British Quadrupeds,' 2nd edit. p. 64, Daubenton's Bat is described as thrusting its nose more or less downwards under its breast in feeding; and in 'The Zoologist,' 1890, p. 99, a captive Pipistrelle is said to have beaten moths against its breast to stun them.