12 January 2023

London Zoo celebrates not so slow start to the year with birth of adorable baby sloth.

London Zoo has shared adorable pictures and footage of its first 2023 arrival - a baby two-toed sloth, born on New Year’s Day. 
Knowing 16-year-old sloth Marilyn was due any day, zookeepers had kept a close eye on the mum-to-be over Christmas and were thrilled to finally spot two big brown eyes peering out through her fur. 
London Zoo sloth keeper Veronica Heldt said: “Having arranged regular ultrasounds with the Zoo’s vet team we knew Marilyn was coming to the end of her pregnancy, so we’ve been checking every day for any sign of the new arrival; we were delighted to finally spot a tiny baby exactly where it should be, clinging onto Marilyn’s tummy, as she curled up in her favourite tree.    
“We’ve nick-named the little one Nova, which means ‘new’ in Latin, as we couldn’t have asked for a better start to the new year.” 
Nocturnal mammals native to South America, two-toed sloths (Choloepus didactylus) have a gestation period of 10 to 11 months and infants are already physically well-developed when they’re born, meaning they’re able to eat solid food right away - and hold on tight to their mother. 
Veronica added: “Sloth babies are very strong when they’re born and immediately find a comfy spot, hugging mum, which they won’t leave entirely until around 12-months-old. This enables them to build up the valuable muscles needed to spend life slowly swinging from tree to tree.”

Baby sloth holds onto mum


Nova was also born with the two-toed sloth’s characteristically impressive claws, which will grow up to four inches in length and also help when the youngster is ready to ‘branch out’ on its own. 
While Marilyn has spent her first week with Nova mostly tucked away from view, visitors to London’s famous conservation zoo may now be able to spot the duo alongside dad Leander in Rainforest Life, the only living rainforest in the city - a lush, tropical paradise, heated to 28°C all year round, which the family shares with titi monkeys, golden-headed lion monkeys and red-footed tortoises.    
Keepers won’t know the youngster’s sex until confirmed by vets after hair DNA is analysed. Male or female, the newborn is a valuable addition to its species and once its sex is confirmed, its details will be added to the European Studbook (ESB), part of a coordinated breeding programme for two-toed sloths.    
Ronnie added: “Every birth at London Zoo is a conservation success and a vital part of ZSL’s work preserving and protecting wildlife. The start of a new year is always cause for celebration, but the arrival of baby Nova has made 2023 extra special.” 
Sloths have evolved for millions of years in a relatively stable climatic environment and are vulnerable to even small changes in temperature and weather - unlike many other mammals, sloths are unable to regulate their own body temperature, and so are particularly threatened by the global issue of climate change. As well as working on the ground to protect threatened species around the world, scientists and conservationists from ZSL, the conservation charity behind London Zoo, are urging world leaders to tackle biodiversity loss and climate change in unison in order to save our planet.    
Visitors to London Zoo can hang out with Marilyn, Nova, and 14,000 other animals this January. Book tickets for today:


  • Adult sloth hanging from a tree at London Zoo
    London’s only living rainforest

    Rainforest Life

    Step into London's only living rainforest, with trees filled with monkeys, snoozing sloths and bats flying overhead!

  • Round-eared sengi
    Macroscelides proboscideus


    Although sengis look like rodents, they are actually more closely related to elephants!

  • Marilyn the sloth at London Zoo
    Choloepus didactylus

    Linne's two-toed sloth

    A sloths’ internal organs, such as the heart, spleen, and liver are all arranged to accommodate living upside-down. 

  • Red titi monkey at Rainforest Life London Zoo
    Callicebus cupreu

    Red titi monkey

    These monkeys mate for life and the male is the main childcare provider, carrying the infant on their back.

  • Book now to visit our animals at London Zoo
London Zoo Newsletter
Get the latest updates about exciting animal news from the Zoos, upcoming events, experiences, offers