The largest animals alive today are mammals. The blue whale is the largest animal ever to have lived and the elephants, giraffes, rhinos and hippos of Africa are the largest land animals you’ll ever see. But not all mammals are big.
So, what is the smallest mammal? A mouse perhaps or a pygmy possum? Neither of these – in fact there are two contenders, depending on whether you go buy weight or by length. Let’s take a look at both.
The Etruscan shrew.
This little fellow is the lightest mammal, weighing from 1.3 to 2.5 grams – about half the weight of a one pence piece. They’re not very long either – even the biggest only make it to 5cm!
Because they are so small, Etruscan shrews have very fast metabolisms. Their hearts beat 25 times every second (ours beat about 70 times a minute). This means that they have huge appetites and have to eat twice their own weight in food every day just to stay alive.
They’re predators and feed mostly on invertebrates, like insects or worms. They will take larger prey though and sometimes eat small amphibians, lizards and the young of other rodents.
Kitti’s hog-nosed bat.
Though heavier than the Etruscan shrew (an average of 2 grams compared to 1.8), this tiny bat is smaller. The largest ones ever measured were only 3.3cm long! That’s the same size as a large bumblebee, hence their other name, the bumblebee bat.
Perhaps due to its tiny size, this species was not discovered until 1973. Their discoverer was a Thai zoologist named Kitti Thonglongya, from whom they get their common name. The ‘hog-nosed’ part comes, unsurprisingly, from their muzzle which resembles a pig’s snout.
These bats are found in only two countries – Thailand and Myanmar – where they dwell in colonies 100 strong, inside limestone caves. Their reliance on particular habitats has made them vulnerable. The burning of the forests where they find their food, plus an invasion of tourists, and even Buddhist monks seeking sanctuary in the bats’ caves, have all had an impact.
Conservation is not just about saving the larger animals, like pandas or polar bears. The little creatures need our protection too. So, spare a thought for the Etruscan shrew and Kitti’s hog-nosed bat. It would be sad for us all if either of these wee wonders were lost.