50 HELLER 



obstacles can stop them. Not unfrequently they ascend very steep, 

 rocky hills. Sometimes their shells are broken and occasionally they 

 are killed by rolling down these inclines, but if uninjured after these 

 falls they will make repeated effors to reascend until crowned by suc- 

 cess. They retire early for the night, drawing in their limbs and neck 

 and after sunset do not move from the place chosen for the night. 

 Darwin, however, states that they travel both day and night when on 

 their periodical visits to the springs. 



All three of the species we observed make seasonal vertical migra- 

 tions. Soon after the rainy season they descend the mountains to the 

 grass covered flats at their bases to feed and deposit their eggs in the 

 light soil. After the grass has withered they again ascend the moun- 

 tains to the moist meadows produced by the trade winds at an elevation 

 of 2,000 feet and above. These migrations are most marked in the 

 dry regions, as at Tagus Cove, Albemarle, but even at Iguana Cove on 

 the same island where there is an abundance of moisture at lower ele- 

 vations a nearly complete migration takes place. On Duncan Island 

 the tortoises scatter out so in the dry season that their movements can 

 scarcely be called a vertical migration. In their seasonal pilgrimages 

 they follow well established trails used perhaps for generations. These 

 trails radiate from the higher plateaus as a center and usually follow 

 the floors of the canyons to the flats below. Some of the trails are of 

 considerable length, requiring several days of persistent effort on the 

 part of the tortoise to cover them. 



When surprised they draw in their limbs and necks with a deep hiss 

 and suspend operations until they think the danger past. No amount 

 of noise seems to frighten them and the Ecuadorians assert that they 

 are deaf. A small one however taken at Iguana Cove, Albemarle, 

 learned to recognize the voice of its keeper in a few months and would 

 come to the gate of its pen when called though the keeper was hidden 

 from its sight. 



The males are sometimes quarrelsome, especially in the breeding 

 season. In fighting the jaws are opened widely and the animals, raised 

 by outstretched necks and limbs to their greatest height, attack one 

 another. Superior height seems to be quite an advantage in a combat 

 allowing the taller to bite down upon the head of his adversary. In 

 these fights they seldom succeed in doing much damage. When 

 turned over on their backs they right themselves by swinging their 

 limbs all in the same direction, which causes the animal to rotate 

 and clear the ground, so that by thrusting out their long necks to the 

 ground and pushing with them the body falls over on the plastron. 



