A 150-year-old Galapagos tortoise died in the habitat where he lived for eight decades, the San Diego Zoo. The tortoise, which was fondly called "Speed," was euthanized on Friday, June 19, after its keepers performed various medical interventions to alleviate Speed's many health conditions.

Speed was approximately 150 years old and for its animal type, this age is considered geriatric and thus several health declines are apparent. Speed suffered from arthritis and other problems, to which his keepers responded by performing physical therapy, hydrotherapy, acupuncture and administering medications.

Speed originated from Isabela Island in the Galápagos chain off Ecuador and first entered the San Diego zoo in 1993. He was brought to the zoo as part of programs that aim to preserve his species, which were then already endangered.

Together with other Galápagos tortoises, Speed once resided at the Children's Zoo, where kids were permitted to ride on their backs - a practice that has long been defunct. In 2010, the gigantic herbivores were then transferred to their new home that cost roughly $1 million. Galápagos tortoises can only be found in the Pacific islands, where Charles Darwin was inspired to come up with the theory of evolution by natural selection.

Male Galápagos tortoises can weigh up to 500 pounds, and females may reach up to 250 pounds, according to the San Diego Zoo's website. These tortoises have such big physique due to a phenomenon called "island gigantism," which pertains to the evolution of animals into gigantic sizes due to isolation or lack of predators in the same island they colonize.

Galápagos tortoises are not very popular compared with other vertebrates such as koalas, pandas, polar bears, elephants and big cats; nonetheless, these animals still get frequent visitors from the members of the San Diego Turtle and Tortoise Society. The members of this group monitor the turtles and help at the zoo by assigning numbers and remembering their personalities.

When Speed was younger, he was considered an alpha male and was observed to butt its leathery head against other male tortoises, signalling arguments about dominance. Speed's death has left the zoo with 13 Galápagos tortoises. The San Diego Zoo was able to produce more than 90 offspring, which were subsequently given away to other zoos. Many of these offspring came from Speed.

Photo: Sergei Scurfield | Flickr