grass and scrublands that overran deforested areas are 

 often, or in time, invaded by native nonforest mice 

 from bordering savannas. 



Most of the arboreal mice and opossums we trapped 

 favored old abandoned banana orchards choked by 

 second growth. As expected, water rats and water 

 opossums were captured in and along streams. Long- 

 nose mice of the genus Oxymycterus were taken only in 

 tall forest. Curiously, these mice were hardly distin- 

 guishable from another species of the same genus col- 

 lected the year before by Hershkovitz in the natural tall 



Bats 



Certain kinds of bats can be easily collected in their 

 roosts during the day. Caves, tree hollows, culverts, 

 tunnels, and buildings are common daytime habitats. 

 The vast majority of bats, however, hide during the day 

 in protected places not easily recognized or accessible 

 to humans or other predators. To catch flying bats at 

 night, we stretched fine-mesh nylon nets made in 

 Japan across flyways, streams, and other places where 

 bats were seen foraging. Fruit-eating bats were most fre- 



Rocky stream habitat of water rats and water opossums. 



grass savanna, or cerrado, of central Brazil. These and 

 the other species of Oxymycterus are currently being 

 studied by Associate Curator Bruce Patterson, head of 

 the Division of Mammals. 



quent victims of the nets. Insectivorous bats, with a 

 much more acute sense of echolocation for prey detec- 

 tion and obstacle avoidance in flight, rarely crashed 

 the nets. 19 



