TR10 - The story of a 17-year-old tamarin

On November 20th of 2014, the golden lion tamarin field team trapped a group of GLTs on the Rio Vermelho ranch in Brazil. One had the tattoo “TR10." Andreia Martins, the team coordinator, was astonished to find that this GLT, a female, was more than 17 years old!  Andreia’s carefully maintained database showed that TR10 had been born on the ranch on September 17, 1997. She was still in good physical condition but her teeth were worn to the gum line. Nonetheless, the observers saw her eating fruits and even insects, and her weight seemed normal. One member of her group was seen carrying two infants. The team could not determine if they had been born to TR10, although she certainly has had many infants over the years.

TR10 in 2015. Photo by Andreia Martins.

The discovery of such an old tamarin raises the question of their longevity. A wild GLT known as “GLT3” was trapped with her family and rescued from a patch of forest that was being cut down by its owner in 1983. GLT3 was one of the first tamarins to be trapped by Jim Dietz in his now-classic field study. She had been born in 1981. Jim relocated GLT3 and her family to the Poço das Antas Reserve, where she survived 10 mates and gave birth to 34 offspring before her death in November 1998, also at the age of 17.

According to Jennifer Mickelberg, who maintains the studbook for captive golden lion tamarins and studies the conservation genetics of wild tamarins, the median age of captive golden lion tamarins is between 7 and 8 years. About 10% of all captive female golden lion tamarins live to be 17. The record age is 31 (a captive male), and the oldest captive female lived to be 25. But mammals generally live longer in captivity than in the wild because they have a steady supply of nutritious food, good veterinary care, and no predators. It’s therefore really noteworthy that TR10 and GLT3 both made it to 17—and that Andreia’s team was able to document these results.

The detailed scientific records that have been kept by GLT scientists for more than three decades reveal some additional interesting details. TR10’s father, known as “T3”, had been born in the Stockholm Zoo in Sweden and had been reintroduced to the wild on the Rio Vermelho ranch in 1992. He had a rocky start in the wild, and had to be rescued several times after he was reintroduced. But he survived and paired up with TR10’s mother, “E6,”who had been born at the Emmen Zoo in the Netherlands and had also been reintroduced in 1992. T3 lived to be 9, but E6 lived to be at least 16 ½ years old. Perhaps longevity runs in families?

Remarkable longevity has a downside. Golden lion tamarins that live too long tend to fill the available breeding opportunities with their many offspring, which prevents unrelated tamarins from breeding.  The result can be an overall increase in inbreeding and loss of genetic diversity. Jim, Jennifer, and Andreia and her team will continue to monitor the tamarins and track their pedigrees. They’ll keep a special eye on TR10.