After penguins were introduced to the Veermata Jijabai Bhosale Udyan and Zoo last month, a new entrant has been welcomed to the family. The hippopotamus population has increased from the existing three at the Byculla Zoo, after a female hippopotamus, Shilpa, delivered a calf weighing 25 to 30kg on Thursday around 4.00 am. This Shilpa and male hippo, Deva’s second calf. Their first, a female calf, was delivered six years ago. Zoo officials said the gender of the newborn calf is yet to be ascertained and will be confirmed only after 10 to 15 days. Shakti,a five-year-old hippo died in 2009 and Jassi, a seven-year-old hippo died in 2010, both due to lung failure.