Nov., 1904.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



271 



proach to a definite estimate of the amount of food a 

 mole will consume in a t;i\en time appears, however, 

 to be one furnished a ijood many years ago by the 

 late Mr. E. R. Alston, an accurate student and ob- 

 server of British and other mammals, .\ceordinij- to 

 this statement, a mole kept in captivitv devoured in 

 the course of a sintjie day an amount of food estimated 

 to considerably exceed its own weii;ht. Durinij the 

 first three days of its captivity it consumed three or 

 four dozen earth-worms, a larijc frot;, a c|U,intity of 

 raw beef, the body of a turkey-poult, and part of that 

 of a second, as well as one or two bl.ick beetles. It is, 

 of course, a t;r>-';'t P'ty ''i-'t ^n accurate record of the 

 weight of the food thus devoured was not kept, but 

 it is quite evident that it was enormous in proportion 

 to the size of the animal by whom it w.is e.iten. .•\nd 

 the marvel of it all is that the mole, like the aforesaid 

 fruit-bat, does not appear to become " stodged " after 

 meals of this description, but in a very short lime is 

 perfectly prepared — nay anxious — to commence afresh. 



Our last instance of voracity in mammals is taken 

 from the cetacean group, and it is of so extraordinary 

 a nature that, were it not attested bv a naturalist of 

 high and unimpeachable authority, it would appear 

 absolutely incredible. The species to which the 

 anecdote relates is the so-called killer-whale, or 

 grampus (Orca g^ladiaior), a highly carnivorous and 

 formidably-armed creature, black and white in colour, 

 and conspicuous on account of its tall dorsal lin when 

 swimming near the surface. It is a by no means in- 

 frequent visitor to our coasts, and is the only cetacean 

 that habitually preys upon warm-blooded animals. In 

 length it varies between about 16 and 25 feet or rather 

 more. No statement as to its weight has apparently 

 ever been published, but, as a very rough estimate, 

 this may be set down as about four or five tons. Ac- 

 cording to the w-ell-known Danish naturalist, the late 

 Professor Eschricht, one of these killers is known to 

 have swallowed four whole porpoises in succession ; 

 w'hile from the stomach of a second, about 21 feet in 

 length, were taken the remains of no less th.in 13 

 porpoises and 14 seals in a more less digested condi- 

 tion ; the brute having been apparently choked by the 

 skin of another seal, parts of which were found cling- 

 ing to its teeth. In quoting the latter half of Professor 

 Eschricht's statement, some writers (notably Mr. F. V.. 

 Beddard, in his " Book of Whales ") omit .ill refer- 

 ence to the more or less digested condition of the seals 

 and porpoises, so that it reads as though 14 entire 

 specimens of the former and 13 of the latter were ex- 

 tracted from the creature's interior, which would be a 

 manifest impossibility. As it is, the statement that 

 four porpoises were swallowed in succession is difficult 

 enough to credit, seeing that a full-grown specimen of 

 these cetaceans measures about five feet in length. 

 There can, however, be no doubt that the killer is an 

 unrivalled glutton among the larger mammals. 



•As regards birds, two or three instances must suilice. 

 The common cormorant (Fhalacrocnrax carbo) is the 

 very tvpe of gluttony, and when gorged, these birds, it 

 is said, will not infrequently continue fishing, although 

 too full to swallow another fish. .After a full meal, 

 cormorants may frequently be seen sitting motionless 

 on a ro(-k for hours, with their wings half extended, as 

 if " hung out to dry." Soon, however, they recover 

 their appetite, and begin to renew their pursuit of 

 prey. The amount of fish a cormorant will destroy 

 during a season must be enormous, and there can he 

 no doubt that the numbers in which these birds exist 



on some parts of our coasts forms a very serious 

 detriment to the fishing interest. 



I'elicans are likewise exireiiu-ly gluttonous birds, as 

 are .also the great adjutant stoiks of India, which, till 

 some years ago, formed such valuable sc.-ivcngers in 

 Calcutta during a considerable part of the vcar, where 

 they might often be seen standing stolidly on the 

 nhiidoii in a more or less completely gorged st:ite. 

 It used to be commonly s.aid in r.-ileutl.i that 

 ;in .-uljutant would swallow even so large a niouth- 

 ful as a dead cat at a single gulp, and there is every 

 reason for believing th.it the statement is founded 

 on fact. 



Many instani-es of gluttony ni'ighl doubtless be 

 found among the lower anim.ils, and cases of the 

 crocodile and the common pike might be cited 

 among such; but to do this would entail :i consider- 

 able amount of space without .iny real increase in our 

 knowledge, bi^yond that which is conveyed in the 

 foregoing Instances. 



What" the special object of the development of 

 gluttonous habits in certain particular kinds of animals 

 may be is very dilTicult to conjeclure. In the case 

 of the mole, which is a very active animal belonging 

 to an aberrant and specialised group, it is_ C|uite easy 

 to understand why an unusually liberal diet may be 

 essential; the diniculty comes in with regard to creatures 

 like the glutton, which differ in no essential features 

 from many of their relatives, who are content with 

 a comniiss.iriat of a moi'e moderate type. 



^^^^^^ 



The ColoroLtiorv of 

 Nestling Birds. 



By W. P. I'vcRAiT, A.L.S., F.Z..S., &c. 



PaLrt I. 



IM the pages of " Knovvikdge " for last year, some 

 may remember, I propounded a theory to account for 

 the differences which obtain between the young of 

 nestling birds in the matter of their activity at the 

 time of their escape from the egg. I propose now 

 to follow this up with a few suggestions as to the 

 probable significance of the coloration of nestling 

 birds. 



This subject falls under two different heads : (a) 

 the coloration of the body as a whole ; and (ji) the 

 coloration of definite regions of the body. ^ Under 

 the first section we have all those birds which are 

 nidifugous, or active from the moment they leave 

 the shell, and some nidicolous or helpless birds. 

 These all agree in that they are downy, but they 

 present different types of coloration, all of which, 

 however, belong to the protective resemblance 

 group. Under the second we have some of the 

 downy forms, and those nidicolous or helpless types, 

 which, though generally coming into the world blind, 

 naked, and helpless, yet frequently exhibit brilliantly 

 coloured markings, generally confined to the mouth. 

 These coloured areas belong to another category, 

 and will be discussed in a future paper. 



The down-clad nestling, there can be no doubt, 

 represents the more primitive condition, but it is iiot 

 so easy to determine whether in any case the primitive 

 type of coloration has also been retained, or whether 



