Here - the lemurs being counted
This equates to more than 1,000 individual animals, as well as colonies and groups of fish, reptiles, and other smaller species, with about100 newborns in 2020.
A spokesman said: "Whilst the teams counting the larger mammals may have an easy task counting their charges, others find it a little more difficult.
"For this reason, many of our fish, bird and insect species are counted as one group rather than as individuals, as these small and quick moving animals can be quite tricky to count and they would be there for hours maybe days trying to count them."