Young great apes sleep with their mothers for four to seven years
Humans are not the only mammals whose young sleep close to their mother or family. Among our closest relatives, the great apes, young share their mother's nest for several years, even long after they can build their own. For most other mammals, things move quickly: in half of all species, the young suckle for less than two months.
What this means
- Among great apes, it is normal for young to sleep with their mother for several years, even once they can build a nest of their own.
- For most mammals, the process is quicker: in only 8% of species do the young suckle from their mother for at least a year.
- Among almost half the species in our sample, the young stay close to their mother or family early in life: in a pouch, on their mother's body or in a nest.
- Animals tell us nothing about what is best for human children.
Where are the young early in life?
64 mammal species from all 27 orders, selected using a fixed rule unrelated to sleep. The sources tell us where the young are kept, carried or hidden, but rarely where they sleep.
31 of 64species: the young stay close to their mother or family at first
Close to their mother or family31
- In their mother's pouch12e.g. short-beaked echidna, southern monito del monte and northwestern marsupial mole
- Carried by their mother10e.g. Robinson's mouse opossum, numbat and northern tamandua
- In a nest or den with their mother6e.g. Brazilian three-banded armadillo, aardvark and chimpanzee
- In physical contact with their mother1e.g. rock hyrax
- With their family or colony2e.g. big brown bat and Baird's tapir
Not close to their mother11
- Hidden alone, with their mother returning to nurse6e.g. black-and-rufous sengi, common treeshrew and hare
- Follows their mother from birth5e.g. African savanna elephant, white rhinoceros and Commerson's dolphin
Not stated in the source22
- e.g. platypus, long-nosed shrew opossum and large hairy armadillo
All 27 orders
- Monotremesplatypus: Not stated in the sourceshort-beaked echidna: In their mother's pouchwestern long-beaked echidna: In their mother's pouch
- Shrew opossumslong-nosed shrew opossum: Not stated in the source
- American opossumsRobinson's mouse opossum: Carried by their motherAceramarca gracile opossum: Carried by their motherAndean white-eared opossum: not counted
- Monito del monte orderPancho's monito del monte: not countedsouthern monito del monte: In their mother's pouch
- Marsupial molesnorthwestern marsupial mole: In their mother's pouchsouthern marsupial mole: In their mother's pouch
- Carnivorous marsupialsbrush-tailed phascogale: In their mother's pouchnumbat: Carried by their motherdibbler: In their mother's pouch
- Bandicootsgreater bilby: In their mother's pouchlong-nosed bandicoot: In their mother's pouchsouthern brown bandicoot: In their mother's pouch
- Diprotodont marsupials (kangaroos, koalas, etc.)coppery brushtail possum: not countedrufous hare-wallaby: In their mother's pouchantilopine wallaroo: In their mother's pouch
- Armadilloslarge hairy armadillo: Not stated in the sourcegiant armadillo: Not stated in the sourceBrazilian three-banded armadillo: In a nest or den with their mother
- Sloths and anteaterspygmy three-toed sloth: Not stated in the sourcenorthern tamandua: Carried by their motherHoffmann's two-toed sloth: Carried by their mother
- Elephant shrewsblack-and-rufous sengi: Hidden alone, with their mother returning to nursefour-toed sengi: Not stated in the sourcerufous sengi: Not stated in the source
- Tenrecs and golden molesRwenzori otter shrew: Not stated in the sourceGrant's golden mole: Not stated in the sourceshort-tailed shrew tenrec: Not stated in the source
- Aardvarksaardvark: In a nest or den with their mother
- ElephantsAfrican savanna elephant: Follows their mother from birthAfrican forest elephant: Follows their mother from birthAsian elephant: Follows their mother from birth
- Hyraxessouthern tree hyrax: not countedrock hyrax: In physical contact with their mother
- Sea cowsdugong: Carried by their mother
- Flying lemurs (colugos)Philippine colugo: Carried by their motherSunda colugo: Carried by their mother
- Treeshrewscommon treeshrew: Hidden alone, with their mother returning to nurselarge treeshrew: Hidden alone, with their mother returning to nursePalawan treeshrew: not counted
- Primateschimpanzee: In a nest or den with their motherbuffy-headed marmoset: Not stated in the sourcesiamang: Carried by their mother
- LagomorphsAmerican pygmy rabbit: Not stated in the sourcehare: Hidden alone, with their mother returning to nurseAmami rabbit: Hidden alone, with their mother returning to nurse
- Rodentssouthern bog lemming: Not stated in the sourcedormouse: Not stated in the sourceColorado chipmunk: not counted
- Insectivores (hedgehogs, shrews, moles)southern short-tailed shrew: In a nest or den with their mothersouthern African hedgehog: Not stated in the sourcebicoloured white-toothed shrew: not counted
- Batslittle golden-mantled flying fox: Not stated in the sourceDayak fruit bat: Not stated in the sourcebig brown bat: With their family or colony
- PangolinsIndian pangolin: In a nest or den with their motherwhite-bellied pangolin: Carried by their motherground pangolin: Not stated in the source
- Carnivoresocelot: Not stated in the sourceshort-eared dog: In a nest or den with their motherNew Zealand sea lion: Not stated in the source
- Odd-toed ungulatesBaird's tapir: With their family or colonylowland tapir: Not stated in the sourcewhite rhinoceros: Follows their mother from birth
- Even-toed ungulates and whalesTibetan antelope: Not stated in the sourcepuku: Hidden alone, with their mother returning to nurseCommerson's dolphin: Follows their mother from birth
Source: Animal Diversity Web (University of Michigan Museum of Zoology); Mammal Diversity Database v2.5 (doi 10.5281/zenodo.21654811).
You may use the graphic under these terms. The studies and measurements the figures are based on belong to those who produced them.
How long do offspring suckle from their mothers?
Weaning ages for the 2,174 mammal species for which this is known. Suckling is not the same as sleeping together, but offspring remain dependent on their mothers for this long.
- Under 1 month60527.8%
- 1-3 months81337.4%
- 3-6 months34215.7%
- 6-12 months24011.0%
- 1-2 years1456.7%
- 2-3 years231.1%
- 3 years or more60.3%
Only 6 species suckle for around three years or longer: Atlantic spotted dolphin, chimpanzee, African elephant and the three orangutan species.
174 speciessuckle for at least one year (8%)
Which species are they?
- Primates99
- Whales33
- Kangaroos and other species20
- Odd-toed ungulates9
- Carnivores6
- Sea cows3
- Elephants2
- Bats1
- Other even-toed ungulates1
Source: Soria et al. 2021, COMBINE, Ecology (doi 10.1002/ecy.3344).
You may use the graphic under these terms. The studies the figures are based on belong to the researchers.
How long do young animals sleep with their mother or family?
Years until the young sleep separately, for species where this has been measured or described.
- Orangutanmother6.6 yearsearliest observed
- Bonobomother6-7 yearsat least
- Chimpanzeemother4-5 yearsat least; some up to 10
- Owl monkeyfamily2.2-4.9 years
- Gorillamotherapprox. 4 years
- Titi monkeyfamily2-3 years
- Beaverfamilyapprox. 2 years1-7 years
- Gibbonmotherapprox. 2 years
- Brown bearmother1.3 yearsup to 2.3
- Koalamother0.5 yearsin the pouch, then on its mother until 1 year old
- Red kangaroomother0.6 yearslives in its mother's pouch
- Polar bearmother0.3 yearsin the den
- Wolfmother3 weeksin the den
Species mature at different rates, so the years cannot be converted into equivalent human ages. Young polar bears, elephants, dolphins and wolves stay with their mother or group for several years, though they do not necessarily sleep together.
Source: Permana et al. 2024; Khayer et al. 2025; Oelze et al. 2024; Savagian and Fernández-Duque 2017; Fernández-Duque 2009; Dian Fossey Gorilla Fund 2019; Souza-Alves et al. 2011; Smithsonian's National Zoo; B.C. Conservation Data Centre; Mayer et al. 2017; Reichard 1998; Yi et al. 2023; Swenson et al. 1998; Van de Walle et al. 2021; Australian Museum (koala); Taronga 2018; Australian Museum (red kangaroo); Andersen et al. 2024; Mech 1992.
You may use the graphic under these terms. The studies and measurements the figures are based on belong to those who produced them.
Orangutans leave home in stages
Ten years of field data from Sumatra, showing when young orangutans learn to build nests and when they begin sleeping on their own.
- 6 monthsInteresse for redebygning
- around 1 yearBygger dagreder
- almost 3 yearsØver sig på natreden
- 3-4 yearsØver mest
- 6.6 yearsFørste hele nat alene (tidligst set)
- around 8 yearsSelvstændig (i gennemsnit 8,6 år)
The young often build their own night nests a couple of metres above their mother's, but regularly move over to hers during the night.
Source: Permana et al., Animal Behaviour 2024.
You may use the graphic under these terms. The studies the figures are based on belong to the researchers.
Some sleep with the whole family
In these species, the young sleep with the whole family or group, not just with their mother.
Titi monkey
Familien sover i klump med halerne flettet ind i hinanden.
Source: Souza-Alves et al. 2011.
Azara's night monkey
Familien sover i klump ved alt fra 5 til 35 graders varme.
Source: Savagian and Fernández-Duque 2017.
Meerkat
Hele gruppen overnatter i samme hule og sover tæt sammen.
Source: Strandburg-Peshkin et al. 2020; Animal Diversity Web.
Naked mole-rat
Kolonien sover i en bunke, op til fire dyr i højden.
Source: San Diego Zoo Wildlife Alliance.
Beaver
Familien sover i hytten af grene og mudder.
Source: B.C. Conservation Data Centre.
You may use the graphic under these terms. The studies and measurements the figures are based on belong to those who produced them.
How we calculated it
The number of years shown for each species comes from field studies, museums and zoos. The lighter area shows the range reported by the sources.
The orangutan figure of 6.6 years is the earliest observation from a ten-year field study, not an average. The claim that some chimpanzees share a nest with their mother until they are 10 years old comes from a secondary source.
Four figures were inferred rather than measured directly: 2.3 years for the brown bear (its third winter in the den), 0.5-1.0 years for the koala (the young stays with its mother), around 2 years for the gibbon (an age group), and that young titi monkeys and owl monkeys sleep in the family huddle until they move away.
The figures for gibbons, titi monkeys, owl monkeys and dolphins are based on the study abstracts.
The brain figure: In humans, 29.9% of brain growth takes place before birth, compared with 40.1% in chimpanzees (DeSilva and Lesnik 2006).
The sample of 71 species: Using a fixed rule, we selected up to three species from each of the 27 mammalian orders in Mammal Diversity Database v2.5, choosing from species with a description of parental care on Animal Diversity Web. 7 species could not be coded reliably and were not included. Each order contributes no more than three species, so the figures apply to the species in the sample, not to the proportion of all mammals.
Only 5 of the 64 descriptions directly mention sleep or rest. The figure therefore shows where the young stay early in life, rather than measured sleep. If a source only says that the young are born in a nest without mentioning the mother, the species is listed under “The source does not say”.
Weaning age comes from the COMBINE database (Soria et al. 2021), which contains figures for 2,174 of 6,234 mammal species. A species is counted under “at least one year” if its young suckle for at least 360 days, as many sources state 12 months (141 species when applying a strict 365-day threshold). For great apes, the database figures are 0.5-6 years lower than those in more recent field studies, so the long tail is more likely too short than too long. The figure for the Tapanuli orangutan is inherited from the Sumatran orangutan.