Christened "Pappi", the semi-aquatic mammal was brought to the Alipore zoo from the Mumbai zoo in 2005.
The male hippo's body was found floating in its enclosure early in the morning.
"It was born in 1986 according to official records and was suffering from the usual problems related to old age. It wasn't eating properly. So far preliminary investigations have not revealed anything unusual," said zoo director Kanai Lal Ghosh.
"Hippos being semi-aquatic, stay inside the water with only their head and back visible but zoo keepers found Pappi's entire body above the water," said Ghosh.
In compliance with standard procedure, a post-mortem examination has been ordered.
"There is a team of doctors on site. They will take samples and do the dissection and analysis as per standard procedure," added Ghosh.
The zoo has three other hippos.
Established in 1876 and spread over 46 acres in the south of the eastern metropolis, the Alipore Zoological Gardens recently kicked off the "Adopt An Animal" scheme for individuals and corporates to augment conservation efforts, spread awareness and boost revenues for the popular tourist spot.
--IANS (Posted on 28-08-2013)