The Etruscan pygmy shrew (Suncus etruscus) is by mass, the smallest known mammal. It has an odd distribution ranging from the Mediterranean to parts of the Middle East, Southern India and Burma. Due to its small size, it has an exceptionally fast metabolism and a heart rate of up to 1500 beats per minute. It mainly feeds on insects, and can tackle prey of the same size as itself. Fortunately this curious animal is not endangered, but it is nevertheless uncommon across most of its range.
Northern collared lemming
The Northern collared lemming (Dicrostonyx groenlandicus) is a mammal species found only in the far north of Canada and Greenland. It is also among one of the most abundant, and despite its body size, survives year-round in cold harsh conditions.
Madame Berthe's mouse lemur
Madame Berthe's mouse lemur (Microcebus berthae) is the smallest primate in the world, at around 9cm long and weighing only 30g. It is named after renowned conservationist and primatologist Dr. Madame Berthe Rakotosamimanana of Madagascar. Endemic to a tiny portion of Western Madagascar, there is thought to be less than 22,000ha of suitable habitat remaining, meaning the total population is likely to be less than 9000 individuals.
Pygmy shrew tenrec
Tenrecs are an odd group placental mammals endemic to the island of Madagascar. Among the smallest is the pygmy shrew tenrec (Microgale parvula) weighing only 3 grams. An unusual feature of tenrecs is their low body temperature, which means that they do not require a scrotum to keep their sperm cool.
By comparison to the old world lemurs, the pygmy marmoset (Cebuella pygmaea) is the smallest of all the new world primates. It weighs just over 100 grams, living in Peru, Ecuador and Western Brazil. Despite being so small (10-15cm), it can leap up to 5m between branches. Unusually for such a wonderful animal, its conservation status is listed as least concern.
Wagner’s Gerbil (Dipodillus dasyurus) is a small, nocturnal, burrowing mammal endemic to the Middle East. In the wild they are social, living in groups and identifying other members of their group by scent. Weighing only 27 grams, females can give birth to litters of as many as nine blind and helpless young.
Looking much like a shrew, the long-tailed planigale is a marsupial from Northern Australia. It is in fact the smallest of all the marsupials, with a skull just 3-4mm high. Just like its larger cousins, the young spend six weeks in a backward facing pouch while they mature. Due to it’s nocturnal behaviours and small size, it is very rarely seen.
Kitti's hog-nosed bat
By some definitions, Kitti's hog-nosed bat (Craseonycteris thonglongyai) also holds the title as the world’s smallest mammal, weighing on average just a few tenths of a gram more than the Etruscan mentioned previously. This bat is however smaller in length at just 30mm. Unfortunately, it has an extremely restricted range in South-East Asia and is currently listen by the IUCN as vulnerable.
Tasmanian pygmy possum
Weighing in at just 10 grams, the Tasmanian pygmy possum (Cercartetus lepidus) is a tiny arboreal marsupial from Tasmania and Southern Australia. Incredibly, this species was actually discovered as a mislabeled specimen in a British Museum. These tiny possums are so hard to study, that a new species was described as recently as 2007.
We’ve all heard of the world’s largest mammals, from whales to bears, elephants to hippos. But could you name the smallest? Dive in below to discover primates the size of your thumb, shrews a little larger than a paper clip and more.