How many baby Rock pocket mouses are in a litter?
A Rock pocket mouse (Chaetodipus intermedius) usually gives birth to around 3 babies.
Upon birth, they weight 1 grams (0 lbs) and measure 3.6 cm (0′ 2″). They are a member of the Heteromyidae family (genus: Chaetodipus). An adult Rock pocket mouse grows up to a size of 10.5 cm (0′ 5″).
To have a reference: Humans obviously usually have a litter size of one ;). Their babies are in the womb of their mother for 280 days (40 weeks) and reach an average size of 1.65m (5′ 5″). They weight in at 62 kg (137 lbs), which is obviously highly individual, and reach an average age of 75 years.
The rock pocket mouse (Chaetodipus intermedius) is one of 19 species of pocket mice in the genus Chaetodipus. (It is sometimes grouped in the genus Perognathus.)Found mainly in rocky outcrops in the deserts of the southwestern United States and Mexico, the rock pocket mouse is medium-sized (length ~18 cm, weight ~12–18g) and nocturnal. It eats mainly plant seeds and makes small burrows in soil close to or under rocks to evade owls, its main predator. The breeding season spans a few months, starting in February or March, and the litter size is typically between three and six. As with most pocket mice, the tail is longer than the body (~10 cm).Historically, rock pocket mice have been subdivided into as many as ten subspecies (Benson 1933; Dice and Blossom 1937) based on geographical distribution and coat colour. Most rock pocket mouse populations have light, tawny fur consistent with the colour of the desert rocks on which they live. However, darker coloured rock pocket mice are found living amid black, basaltic rock formations.In 2003, scientists sampled DNA from both light- and dark-coloured rock pocket mice from areas in Pinacate Peaks, Mexico and New Mexico, USA. In the Pinacate mice, they discovered a perfect association between different versions of the Melanocortin-1 receptor (Mc41r6) gene and coat colour . Subsequent studies demonstrated that there is strong selective pressure maintaining Mc1r allele and coat colour frequencies across the short geographic distances between the light- and dark-coloured rock islands.Thus melanism in rock pocket mice is considered a fabulous example of adaptation by natural selection. Changes in the Mc1r gene sequence are not responsible for the colour difference in the mice sampled from New Mexico, however, leading the researchers to conclude that the almost identical dark coat colours developed multiple times in rock pocket mice, an example of convergent evolution.
Other animals of the family Heteromyidae
Rock pocket mouse is a member of the Heteromyidae, as are these animals:
- San José Island kangaroo rat weighting only 38 grams
- Nelson’s spiny pocket mouse weighting only 67 grams
- Long-tailed pocket mouse with 5 babies per pregnancy
- California kangaroo rat with 2 babies per pregnancy
- San Joaquin pocket mouse with 4 babies per pregnancy
- Goldman’s spiny pocket mouse weighting only 85 grams
- Silky pocket mouse with 3 babies per pregnancy
- Southern spiny pocket mouse with 2 babies per pregnancy
- Nelson’s kangaroo rat with 1 babies per pregnancy
- White-eared pocket mouse weighting only 23 grams
Animals that share a litter size with Rock pocket mouse
Those animals also give birth to 3 babies at once:
- Western chestnut mouse
- Slender squirrel
- Western red-backed vole
- Waterhouse’s swamp rat
- Mountain pygmy possum
- Northern flying squirrel
- Volcano harvest mouse
- Oligoryzomys nigripes
- Damaraland mole-rat
Animals with the same weight as a Rock pocket mouse
What other animals weight around 15 grams (0.03 lbs)?
- Rufous horseshoe bat weighting 12 grams
- Narrow-winged pipistrelle weighting 15 grams
- Canyon mouse weighting 16 grams
- Lesser ghost bat weighting 13 grams
- Ruwenzori shrew weighting 18 grams
- Mindanao pygmy fruit bat weighting 16 grams
- Long-clawed shrew weighting 14 grams
- Cowan’s shrew tenrec weighting 12 grams
- Rufous mouse opossum weighting 14 grams
- Gerbil mouse weighting 17 grams