1904. Moi^FAT. — Bats, Hedgehogs, and Frogs i?i Winter. 83 



whereas with the Bats this sensitiveness to cold is chronic, 

 with the Frog it seems to be merely seasonal. Once the 

 awakened Frog has reached its spawning grounds, a return 

 of cold weather by no means sends it back to slumber. It 

 will be seen from my table that, from January 25th onwards, 

 fresh spawn was being constantlj^ deposited, notwithstanding 

 a long succession of cold and often frosty nights. Even 

 during the period of the Frog's maximum activity (the nights 

 of February 17th to 21st), the temperature remained almost 

 too low for the Pipistrelle to fly, being 42^° on the warmest, 

 and 36^® on the coldest evening of the series. Yet the 

 activity and clamour of the spawning Frogs, in some at least 

 of the pools under notice, was far greater at night than during 

 the comparative warmth of the daytime. 



The spawning of the Frog therefore (if my conclusions 

 are right), requires to be preceded hy some warm nights, during 

 which the creatures can travel under cover of darkness to 

 their spawning pools, and these are often a good half-mile or 

 more from their sleeping places. But it does not need to be 

 conducted on warm nights, and can be carried on successfully 

 at least ten degrees below the temperature at which the 

 hibernating Frog awakes from sleep. 



In explanation of the small number of Frogs observed 

 before the commencement of the spawning season, I must 

 point out that Frogs, when they do come abroad during 

 winter, are much more likely to escape detection than either 

 Bats or Hedgehogs. They are more nocturnal than the 

 Bats — that is to say, they wait until a later period of the 

 evening to come out — and so cannot, like those creatures, be 

 discovered by the unaided eye. The Hedgehog is also, as 

 compared with the Pipistrelle, a late riser- on November loth, 

 1 90 1, I timed three Hedgehogs emerging from their sleeping- 

 place, who came out respectively 58, 88, and 98 minutes after 

 sunset — but the Hedgehog proclaims his whereabouts to the 

 ear, as he moves along with rustling steps and hungry sniffs. 

 The Frog, on the contrary, travels almost noiselessly through 

 the grass, and only betrays his presence when startled by the 

 too close approach of a supposed enem}^ Then the crawling 

 pace is exchanged for that succession of hasty jumps by 

 which everyone knows Ra7ia temporaria ; but to find the Frog 



