Ripan Biswas / Two Blue spotted mud skippers (Boleophthalmus boddarti) fighting at water's edge, Sunderban tiger reserve, West Bengal, India.

Ripan Biswas / Brahminy kite (Haliastur indus) in flight, Sunderban tiger reserve, West Bengal, India.

Ripan Biswas / Bengal tiger (Panthera tigris tigris) strolling among mangrove jungle, Sunderban tiger reserve, West Bengal, India. Endangered.

Ripan Biswas / Brown winged kingfisher (Pelargopsis amauroptera) perched on branch, Sunderban tiger reserve, West Bengal, India.

Ripan Biswas / Collared kingfisher (Todiramphus chloris) perched on branch, Sunderban tiger reserve, West Bengal, India.

Ripan Biswas / Yellow fiddler crab (Uca sp.) portrait, Sunderban tiger reserve, West Bengal, India.

Ripan Biswas / Mangrove tree crab (Aratus pisonii) crawling over tree trunk in mangroves, Sunderban tiger reserve, West Bengal, India.

Ripan Biswas / West Bengal

Ripan Biswas / Mangrove horseshoe crabs (Carcinoscorpius rotundicauda) pair mating in mud at dawn, Sunderban tiger reserve, West Bengal, India.

Ripan Biswas / Mangrove hermit crab (Clibanarius laevimanus) inside of the shell of a mollusc, Sunderban tiger reserve, West Bengal, India.

Ripan Biswas / Mangrove forest, Sunderban tiger reserve, West Bengal, India.

Ripan Biswas / Red fiddler crab (Minuca minax) female, portrait, Sunderban tiger reserve, West Bengal, India.