388 EXTINCT AND VANISHING MAMMALS 



paca (Cuniculus). The present animal, however, is extraor- 

 dinarily different in its stout, heavy appearance and thick 

 tail of about half the body length. Goeldi describes the gait 

 as "waddling" on account of the plantigrade position of the 

 feet and the shortness of the legs, while the whole appearance 

 "reminds one of an immense rat well advanced in develop- 

 ment towards a bear." Of his captive animals Goeldi (1904) 

 writes that they are "of a peaceful, phlegmatic disposition," 

 exhibiting as a predominant trait "a combination of leisurely 

 movements and supreme good nature . . . It is not easily 

 irritated, and permits one to stroke and to scratch its head 

 and back, and only occasionally manifests its displeasure by a 

 low guttural growl. I have never yet observed a manifest 

 intention to bite. When let out of the cage it makes no attempt 

 to escape, and limits its excursions to an exploration of the 

 immediate neighborhood in search of something to eat . . . 

 This phlegmatic disposition seems to me to be a very precarious 

 endowment for the struggle for life ; and considering the evident 

 advantages which result to the smaller domestic rodents . . . 

 from their nervously active constitution, it would not be 

 strange if the species should tend to disappear. The apparent 

 rarity of Dinomys may possibly find its explanation in the con- 

 sequences of such a psychological endowment in a more 

 nervous environment; but it is also possible that this rarity 

 is because of the circumstance that the real habitat of the 

 species has not yet been ascertained." Goeldi's captive 

 female shortly gave birth to a young one and died in unsuccess- 

 ful parturition of the second fetus, so that two young at a 

 birth is probably normal, indicating a slow rate of increase 

 (see also Tate, 1931). Dr. Mohr corroborates Goeldi's account 

 of the slow and gentle behavior of the animal. 



Heller, who secured the series in the Field Museum, is the 

 first to have gleaned much information as to the habitat of the 

 species, and owes the skulls he secured to the habit of the 

 natives of the upper Huallaga River of preserving the skulls 

 of the game they kill, hanging these in their huts for good luck 

 in hunting. He states (in Sanborn, 1931) : "It is not a fighter 

 but merely fights as a last resort to save its life. It is slow in 

 motion and can not turn about quickly, therefore it has no 

 rear protection from alert foes like ocelots, tayras, coatis, etc. 

 It therefore lives in rocky cliffs, or holes in the ground by 



