Gramma, a Galápagos tortoise residing at the San Diego Zoo, died on Thursday at an estimated age of 141 years.
Her birth year is approximated to be 1884. During this period, Chester Arthur served as U.S. President, and the United States comprised 39 states. Historical events occurring around her estimated birth included the completion of the Washington Monument, the cornerstone placement for the Statue of Liberty's pedestal, and the establishment of the Greenwich prime meridian.
Gramma had been a resident of the San Diego Zoo since approximately 1928, having transferred from the Bronx Zoo in New York after being acquired from the Galápagos Islands. The zoo confirmed that she was receiving expert support for age-related conditions, leading to a compassionate euthanasia decision.
Longevity in tortoises is attributed to their slow biological processes. Steven Austad, a biology professor, states that the gradual accumulation of biological damage in these species contributes to their extended lifespans. This characteristic is consistent with other documented long-lived Galápagos tortoises, including one that died at Reptile Gardens at approximately 130 years, Lonesome George at over 100 years, and 'Speed' at the San Diego Zoo at about 150 years. Goliath at Zoo Miami recently marked its 135th birthday. Stephen Blake, an assistant professor of biology, suggests their physiology may facilitate a 'physiological oil change' that aids in neutralizing toxic compounds.
Galápagos tortoises are hypothesized to have migrated to the islands from the South American mainland via water. Their physical adaptations, such as a long neck for snorkeling and a buoyant, bell-shaped body, would have aided in oceanic travel. Genetic analysis indicates that the entire Galápagos population originated from a single female arriving between 2 million and 3 million years ago; female tortoises can store sperm for up to seven years.
Male Galápagos tortoises can exceed 500 pounds and reach 6 feet in length, with females typically half that size. The classification of their evolutionary size remains under scientific discussion, considering the existence of larger extinct mainland species.
Currently, 15 subspecies of Galápagos tortoises exist, with three considered extinct. Gramma's birth occurred a few years after the death of Charles Darwin. It is considered probable that tortoises alive today could have been present on the Galápagos Islands during Darwin's visit in 1835.