ANIMAL BEHAVIOR—ERNEST P. WALKER 279 
but we can judge from its structure that it probably eats insects or 
other soft animal food. The food of carnivores, the flesh eaters, is 
rather uniformly flesh or fish, but carnivorous animals frequently pass 
over the principal meaty portions of a carcass to drink the blood 
and eat parts of the viscera, thereby obtaining valuable vitamins. 
Almost invariably the glands or other parts which they eat are known 
to scientific workers as being excellent sources of vitamins. In one 
experiment that was conducted under my direction, we separated 
chicken viscera into its various component parts and then offered 
these to small carnivores. Almost all immediately chose the pancreas, 
which suggests that it is probably a valuable food. Most people 
have witnessed a dog burying a bone and later digging it up and chew- 
ing on it. It is possible that the bacteria of the soil act on the bone 
to make it more palatable and more digestible and possibly to elimin- 
ate any danger of ptomaine poisoning. A few carnivores, such as the 
binturong (Arctictis) and the palm civets (Paradozxurus and related 
genera), have taken to a diet consisting largely of fruit. 
An ingenious method was once demonstrated to me by the West 
African marsh civet or marsh mongoose (Atiliz paludinosus) in the 
National Zoological Park. This animal, about the size of a large cat, 
had a remarkable method of breaking bones. He was commonly 
given two pieces of horse ribs 4 inches in length and, when he had 
eaten most of the meat off of them, he would take a piece of bone 
between his forepaws, raise himself up on his hind feet with the hind 
legs well extended and with his forepaws well above the level of his 
head, and then quickly throw the bone down on the cement floor of the 
cage from a height of 2% to 3 feet. If he was not satisfied with the 
results of the first throw, he would repeat the process. The pro- 
cedure described suggests that these animals probably use the same 
methods in breaking the shells of mollusks and land crabs on which 
they feed in their native haunts of West Africa. 
The shortest mammal in the Americas and almost the smallest in 
the world is the lesser short-tailed shrew (Cryptotis parva) which 
inhabits the eastern United States. It weighs as much as two dimes, 
less than one-fourth of an ounce, and naturally such a tiny creature 
cannot cope with large antagonists in the usual manner. It normally 
lives in loose soil and leafmold where it feeds on earthworms, insects, 
and a wide variety of small animal life including frogs. Even a 
vigorous earthworm is a difficult creature for the tiny shrew to subdue 
in the usual manner, but earthworms lose their activity within a few 
seconds after the shrew gives them a few light bites; sometimes a 
single nip will suffice. Apparently the saliva carried into the very 
minor injury made by the shrew’s teeth is poisonous to the earthworms 
and takes effect very quickly. When the earthworm has become 
quiet the shrew proceeds to devour it, and it may be that this special- 
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