One of the tiny apes from Indonesia was dead, while the other, in a video shared by Indian Customs, was seen cradled in the arms of an officer, softly hooting before covering its face with its arm.

Customs said the passenger, who had travelled from Malaysia via Thailand, was given the rare apes by a wildlife trafficking "syndicate" for delivery in India.

Officers acting on "specific intelligence" arrested the passenger in Mumbai on Thursday.

"A subsequent search of their checked baggage, a trolley bag, led to the discovery and seizure of two Silvery Gibbon (Hylobates moloch), one live and one found dead, which were concealed in a basket," the customs department said.

Wildlife trade monitor TRAFFIC, which battles the smuggling of wild animals and plants, warned in June of a "very troubling" trend in trafficking driven by the exotic pet trade.

More than 7,000 animals, dead and alive, have been seized along the Thailand-India air route in the last 3.5 years, it said.

Home in the wild for the small Silvery Gibbon is the rainforests of Java in Indonesia.

They are threatened by the loss of forests, hunting and the pet trade, according to the International Union for Conservation of Nature.

Estimates for the primates left range from about 2,500 to 4,000.

The seizure follows several recent smuggling busts at the same airport.

Just a week earlier, customs officials said they had arrested another smuggler carrying snakes, tortoises and a raccoon.

In June, Mumbai customs intercepted two passengers arriving from Thailand with dozens of venomous vipers and more than 100 other creatures, including lizards, sunbirds and tree-climbing possums, also arriving from Thailand.

In February, customs officials at Mumbai airport stopped a smuggler with five Siamang Gibbons, an ape native to the forests of Indonesia, Malaysia, and Thailand.