The twins in question are baby pygmy marmosets – tiny offspring of what is already the smallest monkey in the world, even when fully grown.
Mum and Dad pygmy marmoset only set up their family home at the Aquarium in early April, but seemingly found their rainforest-themed habitat extremely comfortable, mating almost straight away.

Six months on, the result is two of the cutest, yet most camera-shy creatures imaginable. Mum is 4.5 years old and Dad just 2.5 years of age and both are proud first-time parents, taking turns at looking after their new arrivals and loving every minute of their newfound responsibility.

The tiny baby pygmy marmosets can only currently be spotted by the very keen-eyed. They appear as furry lumps on the backs of their parents – most often their father.

He hands the little darlings over to mum for suckling, which is when some visitors catch extraordinary glimpses of the minute, loveable creatures.

The displays team estimate that the babies only weigh around half an ounce, but that is already around one sixth of the weight of their little parents. In real terms, this is a big deal as baby pygmy marmosets have the largest birth weight ratio of all, when compared to the baby-mother weight ratio of other monkeys. Human babies actually weigh only around one-nineteenth of the weight of their mothers!

Marketing manager, Charlotte Brown, says: "We are extremely proud to have these tiny babies in our care and are letting Mum and Dad get on with their parenting skills without too much interruption.

Our marmosets have been much loved since they arrived in our rainforest zone in early April and their new babies are absolutely adorable.

Visitors are already arriving with the sole intention of trying to see our new twins."

Those who do wish to see these tiny monkeys can visit the Lakes Aquarium, at Lakeside, near Newby Bridge, seven days a week. Current opening hours are 9am to 5pm.

Updates on the progress of these little babies will soon be available online at www.lakes aquarium.co.uk