The Thiruvananthapuram Zoo, one of the oldest and the best in the country, actually forms part of the Botanical Gardens. The zoo was established as an annexe to the Napier Museum in 1857 by Maharaja Swati Thirunal, the erstwhile maharaja of Travancore.

Spread over 55 acres of land in the heart of Thiruvananthapuram, the zoo which is set among woodlands and lakes is a natural habitat for the animals. The zoo provides people from all over the country a chance to watch 75 different species of animals from India and abroad. The Lion tailed Macaque, Nilgiri Langur, Nilgiri Tahr, Indian Rhino, Asiatic Lion and the Royal Bengal Tiger are the prominent attractions of the zoo. An aviary and a reptile house with different varieties of poisonous and non-poisonous snakes are located within the premises.

The snake house at the Thiruvananthapuram Zoo, which is nearing completion, would be the nocturnal home for housing creatures such as the slender lorris, jungles cats and porcupines. The reptile house and the open enclosure for the panther are the last major construction works in the ongoing modernisation project at the Thiruvananthapuram Zoo. The entrance to the snake house resembles the head of the snake as the overall structure resembles the undulating body of a snake in motion. The king cobra and the python, however, would have enclosure twice as big. The speciality of the snake house is that each of these cubicles would have a `micro-climate' designed to simulate the natural habitat of each variety of snake. The zoo plans to add five new species of snakes to its collection once the snake house is operational. The exit point of the snake house will serve as the entrance to the rest of the reptile house that would be the home of the crocodiles, the turtles and the monitor lizard.

The Botanical Garden, also within the zoo premises, has varied specimens of tropical plants and trees.