SECRETARY'S REPORT 105 



portion of their body, jump from an elevated location, and glide 

 downward through the air. 



BIRTHS AND HATCHrNCS 



Conditions under which animals are kept on exhibition are usually 

 not favorable for breeding or raising young. However, occasionally 

 young are born or hatched that are of outstanding interest to the 

 public, and are valuable as additions to the group, or for exchange. 



The giraifes {Girajfa camelopardalis) produced two young during 

 the year. It would be pleasing to have a considerable herd of giraffes 

 that could be built up from the young that are born here, but accom- 

 modations are not adequate for a large group of these animals, and 

 so the young are used in exchanges to obtain other animals that are 

 needed. 



The Chinese water deer {Hydro'potes inermis) produced three 

 young that survived during the year. This rate of increase is rapidly 

 building up an excellent group of these attractive little animals. 



During the year the colony of pygmy hippopotamus {Choeropsis 

 liberiensis) gave birth to two young. These are valuable animals and 

 the surplus is exchanged for other species, the last one helping to 

 pay for a young rhinoceros. 



The little colony of the rather showy slender-tailed cloud rats 

 {Phloeomys cwiniiigi) is gradually increasing. This year there were 

 two births of one each. Both young are thriving. 



The hybrid Alaska brown bears {Ursus gyas) and polar bears 

 {Thalarctos maritwvus) again produced a litter of three cubs, but 

 unfortunately the young did not live. 



The group of African porcupines {IJystrix galeata) was augmented 

 by the birth of one more. The care that is given the new-born young 

 is an outstanding demonstration of a group defending its young. 

 The parents and older brothers and sisters keep the young between 

 them almost constantly and maintain an unbroken front of long sharp 

 spines projecting in all directions around the baby. 



Barbara, the female hybrid gibbon {Hylobates agilis X H. lar 

 pileatii-'i) gave birth to a baby that unfortunately lived only about a 

 week. 



The pacas {Cuniculus paca) produced another young. 



The crested screamers {Chauna torquata) hatched two eggs. Not 

 only were these two birds very desirable additions to the collection, but 

 the growing young are attractive and arouse much interest. 



The colony of black-crowned night herons {Nycticorax nycticorax 

 hoactli) continues to thrive as it has for many years, and this year 

 raised 12 young. They are not rarities, but it is interesting to note 

 that they do well in captivity. 



The sharp-tailed sand boas {Eryx thebaicus)^ received from Dr. 

 Kuntz, produced five young that are thriving. 



