Guwahati: Pobitora wildlife sanctuary, which has the world's highest density of one-horned rhinoceros, has hit a century.

The rhino estimation, which was carried out on Sunday, found 102 rhinos. There were 93 rhinos in the 2012 census.

The sanctuary is situated in Morigaon district.

Spread across an area of 38.8 square kilometres, the rhino habitat, however, is confined to a mere 16 square km area of the sanctuary.

"The only way for the survival of the rhinos is to translocate them," divisional forest officer of Guwahati wildlife division, Pradipta Baruah, told The Telegraph.

Altogether 10 rhinos have been translocated till now from Pobitora to Manas National Park under the Indian Rhino Vision 2020.

Sources said intense cattle grazing in Pobitora has forced rhinos to stray out of the sanctuary. The straying of the rhinos to nearby unprotected areas has also made them an easy prey for poachers.

In 1987, the number of rhinos was 54, 56 in 1993, 68 in 1995, 74 in 1999 and 81 in 2006, and 84 in 2009.

No research has been conducted on the ideal space required for the rhinos in a sanctuary.

Of the 102 rhinos found on Sunday, 28 are male, 43 female, 11 are sub-adult female, 8 calves are below one year and 12 are above one year.

The entire park was divided into seven blocks with officials on elephants counting the rhinos.

Baruah said 26 rhinos had died in the sanctuary since 2012 of which six succumbed to poachers' bullets.

A study carried out by Aaranyak, an NGO working for preservation and restoration of environment few years back, had identified three major tracks through which rhinos stray out of the wildlife sanctuary.

These tracks are Kholabhuyan-Sildubi-Bonmuri-Murakata-Duboritoli/Hatimu-ria-Gagoldubi-Patekibori, Tamolidova-Kanjuli-Bhekenipathar-Hiloikhunda-Kurua and Kumarpur-Borbeela-Digaru. These tracks have been marked using GPS.