As the Zoological Society of London (ZSL) celebrates its bicentennial as a charity, staff at London Zoo have commenced their annual inventory of every resident animal.

The zoo is home to an impressive collection of over 8,000 creatures, ranging from a group of leafcutter ants to critically endangered Asiatic lions.

Established in 1826, ZSL operates London Zoo as a charity focused on science-driven conservation, dedicated to safeguarding species, revitalizing ecosystems, and fostering harmony between wildlife and human populations.

During the yearly census, each animal is documented, fulfilling a licensing obligation and providing valuable data for international conservation breeding initiatives.

Recently, key species have seen population boosts thanks to new births.

In July 2025, the population of Humboldt penguins expanded with the hatching of 16 chicks in one season—a significant achievement for this vulnerable species, which hails from Chile and Peru and is experiencing declining numbers in its natural habitat.

Additionally, in April, the hatching of eight Socorro dove chicks was celebrated, signifying a significant advancement in the fight against extinction for this species.

Once thought to be extinct in the wild, there are now only 180 Socorro doves worldwide, cared for by fewer than 50 conservation organizations.

Last year also witnessed an increase in critically endangered Darwin’s frog populations, with eight new individuals born. These frogs, part of the EDGE species group (Evolutionarily Distinct and Globally Endangered), face threats from a lethal chytrid fungus.

ZSL conservationists regarded these births as a milestone in their efforts to protect the species on an international scale.

Dan Simmonds, the head keeper at London Zoo, stated: “Every aspect of our conservation work here at London Zoo plays a crucial role in ensuring we maintain a secure, sustainable population of many critically endangered and, in some cases, extinct-in-the-wild animals.”