Tara the elephant first came to the Toronto Zoo in 1974. ((Toronto Zoo))

An elephant described as the matriarch of the Toronto Zoo's elephant herd has died at age 41.

Tara was found lying down Monday morning, officials said. 

Staff could not get the 3,855-kilogram animal back on her feet.

Tara had not exhibited any recent signs of ill health, and a post-mortem will be conducted to determine a cause of death, they said.

The average lifespan of elephants in captivity is 40 to 45 years.

The largest of the zoo's elephants, Tara was also described as "the boss."

The African elephant arrived at the Toronto Zoo in 1974, shortly after it opened.