XXIII 



THE ECONOMIC RELATIONS OF MAMMALS TO 



INVERTEBRATES OTHER THAN 



INSECTS 



Probably most of the mammals that eat insects also indulge in other 

 arthropods, worms and non-shell-bearing mollusks, and some of them 

 take shell-bearing mollusks also. A few examples only need be given. 

 The duckbill of Australia takes crustaceans and worms. Coyotes, wild- 

 cats and raccoons have been known to eat crustaceans. 1 A considerable 

 part of the food of moles and some of the food of shrews consists 

 of earthworms. 2 In 306 mole stomachs the contents averaged 72.5 per 

 cent earthworms, with some insects and slugs. 3 In 56 other stomachs 

 the average was 26 per cent earthworms, i per cent arachnids. 4 In 

 91 stomachs earthworms and beetle larvae formed the bulk of the 

 food, with a few millipedes and centipedes. 5 One captive mole ate 48 

 earthworms and 7 cutworms in 10 hours. 6 One California stomach was 

 "filled with angleworms." 7 



Minks, skunks and otters sometimes eat crustaceans, the mink, at 

 least, including also mussels. 8 Muskrats are especially fond of fresh- 

 water mussels and eat also snails and crustaceans. 9 Rats have been 

 known to eat fresh- water snails of the genus Lymnaea Short- tailed 

 shrews are very fond of land snails, one having eaten 130 Poly gyros in 



1 Lantz, U. S. Biol. Surv. Bull. No. 20, 1905. Howell, N. Amer. Fauna, No. 45, pp. 

 35, 42, 1921. 



- Hisaw, Journ. Mammalogy, iv, 9-20, 1923. Scheffer, Farmers' Bull., No. 1247, 

 1922. Howell, N. Amer. Fauna, No. 45, pp. 20, 21, 1921. Bailey, ibid., No. 49, pp. 200, 

 205, 1926. 



3 Wight, Journ. Mammalogy, ix, 19-33, 1928. 



4 West, Bull. Illinois State Lab. Nat. Hist., ix, 1910. 



6 Dunnam, Iowa Agric. Exper. Sta. Circular No. 88, 1924. 



6 Howell, Journ. Mammalogy, iv, 253, 1923. 



7 Dirks, California Fish and Game, v, 99, 1919. 



8 Howell, N. Amer. Fauna, No. 45, p. 37, 1921. Bailey, ibid., No. 49, pp. 173, 179, 

 1926. Johnson, Roosevelt Wild Life Bull., m, 247, 1925. Lantz, Farmers' Bull., No. 

 587, 1914. Ashbrook, U. S. Biol. Surv. Leaflet No. 8, 1928. 



9 Lantz, The muskrat, Farmers' Bull., No. 396, 1910. Johnson, Roosevelt Wild Life 

 Bull., in, 240, 247, 1925. Howell, N. Amer. Fauna, No. 45, p. 35, 1921. Bailey, N. Amer. 

 Fauna, No. 49. p. 187, 1926. Lee, Journ. Trenton Nat. Hist. Soc., No. i, p. 8, 1886. 

 Apgar, ibid., No. 2, pp. 58-59, 1887. Butler, Amer. Naturalist, xix, 1044-1055, 1885. 

 Headlee, Biol. Bull., xi, 305-318, 1906. Baker, Biol. Bull., (2), vn, p. 18, 1922. 



10 Smith, Limnaea stagnalis destroyed by rats, Journ. Conch., xvi, 141, 1920. 



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