At least four nilgais have died in the Marchazar Zoo within a week apparently due to cold weather as the officials concerned did not construct huts to keep the animals warm at night. Sources said the nilgais died one after the other in the zoo which lacks proper facilities for the captive animals. During the last four years, around two dozen animals, including zebras, an ostrich, lion cubs, a bear, urails and nilgais died in the zoo apparently because of the negligence of the staff. But officially the authorities termed the death of the animals "natural". In August last year, six deer were killed by a wolf at the F-8 enclosure, an extension of the zee, due to the absence of any staff there.