REPTILIA 239 



trial habits. If put in the water they soon drown. They are, Uke the 

 pond tortoises and unhke the giant land tortoises, largely carnivorous. 

 In captivity they become very tame and are often used as pets. There 

 are records of individuals having hved in captivity for fifty years or 

 more. They bask in the heat of the sun most of the day, but at dusk 

 they become active, hunting for slugs and worms, which form their 

 chief diet. At night they retire to their burrows. Their nesting habits 

 are much like those of the pond tortoises. 



The true land tortoises range from forms of moderate size, like Tes- 

 tudo groeca, the common European species, to the giant land tortoises 

 of the oceanic islands (Fig. 134, C). These creatures do not differ 

 materially from others except in size, a character which may have 

 been the result of the easy conditions of life on oceanic islands or it 

 may be merely one of the effects of senescence. They are herbivorous 

 and devom* quantities of young plant shoots and other succulent 

 vegetation. In the Galapagos Islands there is a different species of 

 land tortoise for almost every island. It is believed that the first in- 

 dividual or pair of these animals reached the Galapagos land mass 

 when it was a single small continent, that subsidence of that part of 

 the earth's crust left only the high places above water, and that these 

 are the present islands. Isolation of the tortoises on the different 

 islands is supposed to have been the principal agency in establishing 

 different species on the various islands. The largest specimens of land 

 tortoises weigh over five hundred pounds and are over four feet in 

 length of shell. They are said to exhibit remarkable longevity, some 

 having a record of about one hundred and fifty years. 



Family 6. Chelonidse (Sea Turtles). — ^This group is best known 

 for the so-called tortoise-shell, a product derived from the horny 

 scutes with which the carapace is covered. They are large turtles 

 with paddle-Uke limbs, small head, short neck and rudimentary tail. 

 They come ashore only to lay their eggs in the beach sand of the trop- 

 ical sea-shores. At that time they are captured in large numbers and 

 brought to the metropolitan markets, where their flesh meets with a 

 ready sale as a material for soup. When they are out of th« water they 

 are very clumsy and are easily caught. All that the hunter has to do 

 to capture his prey is to turn it over on its back, where it is safe until 

 such time as it is convenient to load it into boats. Usually they are 

 kept in water-filled inclosures till needed and shipped ahve to the 

 market. 



