The area supports rich biodiversity including mangroves and mangrove associates (71 species), largest population of estuarine crocodiles (1358 as per 2004 census), the rare white crocodile (Sankhua), largest Indian lizards (water monitor), poisonous and non-poisonous snakes like king cobra and python, varieties of resident and migratory birds (217 species) and number of mammalian species (spotted deer, sambar, wild boar, fishing cat, jungle cat, otter etc.) In comparison to the national status, the composition of vertebrate fauna / species of Bhitarkanika project area represents 8% mammals, 17.70% birds, 9.40% reptiles and 2.5 % amphibians. The Gahirmatha sea beach, bordering the sanctuary attracts hundreds and thousands of Olive ridley sea turtles for mass nesting / egg laying (World's largest rookery) during the winter months (January to April).
Bhitarkanika is endowed with a very complex and dynamic ecosystem and is highly fragile in nature. The ecosystem is complex in a sense that all the sub ecosystem namely fresh water, marine and terrestrial is intricately mixed with each other. The essential factor for maintenance of such ecosystem is regular influx of fresh water from adjoining land and tidal inflow from the sea. Any change in the regime of either factor is likely to effect a corresponding change in the mangrove ecosystem.

Depending upon the degree of inundation, the species composition, richness and diversity varies. Since the area contains older formations and newly accreting landmass, several horizontal zonation of plant communities are met with. The horizontal and vertical zonation of plant communities influenced by influx of fresh water degree of inundation, seasonal rainfall and salinity gradients greatly influence the status of wildlife, their number and distribution.

Mangrove areas support a range of interconnected food webs, which directly sustain the fisheries. Algae and detritus sustain shrimps and prawns, which provide a food source for species such as Bhekti (Lates sp.) Cat fishes etc. Fish and prawns spend most of their adult life at sea and return to the mangrove areas and vice versa to spawn. Some of the commercially important fishes are Ilisha, (Hilisa illisha), Khainga (Mullet sp.), Bhekti (Lates calcarifer), Kantia (Mustus gulia), Kokill (Anchovella sp.) etc. Prawns such as Penaeus indicus, tiger prawn (Penaeus monodon), Metapenaeus affinis and crabs, mainly the mud crabs (Scylla serrata) are exploited in large numbers by the fishermen both in the breeding and non-breeding seasons. Mud skippers, a typical fish reside around and in mangroves. These fishes are able to survive short periods of aerial exposure, skip around on the water and mud and build chimney like burrows.

The Saltwater crocodile "rear and rehabilitation" operation is a success story in Bhitarkanika and the crocodile population in the Bhitarkanika river system has been gradually built up. The captive reared young crocodiles have been released in the creeks and estuaries and above 2200 crocodiles have been released in phases since 1977. Some of the released crocodiles have bred successfully in the wild and above 45 clutches of eggs have been located, which is 6.5% more in comparison to 1975-76.

The sea beach, bordering the sanctuary attracts thousands of olive ridley sea turtles for mass nesting/ egg laying during the winter months (January to April). Bhitarkanika mangrove ecosystem is unique of its kind and it is a best reptile refuge in the entire country. The sanctuary is home to a number of birds and every year a large number of migratory birds come to nest into the mangrove area. The other animals that you can see at the Bhitarkanika sanctuary include King Cobra, Indian Python and Water Monitor Lizard.

Every year large number of Olive Ridley Sea Turtles flock at the Gahirmatha coast to lay their eggs. These turtles attract a number of wildlife enthusiasts to Bhitarkanika National Park.

Encroachment of forestland by the migratory people and conversion of the same into common homestead and agriculture land are the main problem in this locality. This has put tremendous biotic pressure on the potential mangrove forests. In the encroached land, the tidal creeks are being blocked by earthen bunds, which prevents the natural tidal flow and gradually the mangrove vegetation perish from that area.There are known pollution causing Industries like Oswal and PPL, etc. around Bhitarkanika which could affect the ecological soundness, use of chemicals and pesticides in agricultural fields and effluents coming from large number of prawn gherries has some impact on the wildlife depending on the aquatic habitat.

To wean the poachers away from poaching, a massive awareness programme has been undertaken The efforts are supplemented with the establishment of anti-poaching camps at strategic points. To encourage eco-tourism, training camps for eco-guides and boat-man associations are being organized.

Communication: - By Motor boat from Chandbali.