Jane Healy, Auckland Zoo
Here at Auckland Zoo, we’re excited to share that a fifth Galápagos tortoise hatchling emerged from its shell in early November!
This welcome newcomer – a lockdown arrival – follows the hatching of four Galápagos tortoises in late January to parents, mum Chippie (51) and dad Smiley (50).
Weighing just 80.1grams, and taking 119 days to hatch, this hatchling was the one of three undamaged eggs salvaged from a clutch laid by Chippie on 12 July – and the only fertile one.
“Throughout its incubation we tracked this one super closely and could see it developing in the egg. We recorded and took photos of its growth every week, and as a team we tweaked a few things, having learnt from the January hatches,” explains the Zoo’s Galápagos tortoise species coordinator Sonja Murray.
“However, we weren’t holding our breath that we would achieve another success and didn’t want to count our Galápagos tortoises before they hatched!
“It’s exciting that we have been successful and reinforces that we’re on the right track and that Chippie is reproductively healthy, which is great.”
Ectotherms’ incubation coordinator Nick Reynolds manages the exacting science of incubating reptile eggs at the Zoo, and explains monitoring and patience are a big part of the job. In the case of Galápagos eggs – incubation is at precisely 29.5 degrees Celsius.
“The second month into the incubation, I candled (shone a torch onto) the egg and could see blood vessels – an indication it was fertile. We did this every week, and very gradually the view of the blood vessels was replaced by the shadow of the growing tortoise, and then it was just a matter of waiting patiently for a tortoise to pop out,” says Nick.
On the morning of the 7 November, Nick arrived to see one grey shape and two white shapes (the other two eggs) through the incubation window. “Today’s the day” he called out to Sonja – who was given the honour of opening up the incubator door to be the first to witness this precious new hatchling, having missed that opportunity back in January.
Nick explains as newly hatched Galápagos tortoises can stay underground for 30 days while they absorb their egg’s yolk sac (their initial food source) and allow their plastron (the belly of the shell) to heal over, this little one will stay in the incubator for a 30-day period.
In time, this hatchling will join the other four hatchlings in the raised island (creche) home within the adult Galápagos tortoise indoor habitat - where visitors can get a great view of them.
However, the Zoo’s Ectotherms Curator, Don McFarlane explains “young Galápagos tortoises are known to squabble over food, so initially once it can be moved here, we’ll have a partition for this hatchling that’s a good 10 months’ younger, to provide individual care.”
This keepercam by ectotherm keeper Sonja shows this tiny tortoise when it first hatched
The science of care - learnings
Don says he, Nick, Sonja and all the team have gained valuable knowledge through caring for the first four hatchlings – that all going well, along with this fifth arrival, will eventually grow 2,500 – 4,000 times in body mass and could live for over 180 years!
“We know that keeping the substrate (floor) predominantly dry is important for the health of the underside of the shell (or plastron) and it’s important to ensure the substrate is undulating for climbing. Though occasionally juvenile tortoises may find themselves on their backs after misjudging our little ‘hills’, it’s an important life skill to learn to right themselves.”
“In addition to refining heating and lighting technology, which is ongoing, once they start eating – from a diet perspective, we’ve also found chopping up their hay extremely finely is an excellent way to enable them to eat large amounts, which they need to grow.”
Naming competition for hatchlings this summer!
As yet, the Zoo five Galápagos tortoise hatchlings are without names. But later this summer, we’ll be running a naming competition on site – that all visitors to the Zoo will be able to enter. Keep an eye on our social channels – as it’s here we’ll share updates about these hatchlings and announce details of this naming competition.
