In humans, pregnancy lasts nine months. But what about other animals? The duration generally depends on the size. But there are exceptions.
The bigger it is, the longer it is, as the well-known adage goes – or thereabouts. In the elephant, the largest land animal, the gestation period is 22 months, almost two years. It happens that the umbilical cord is cut while the baby is still in its mother’s womb. This is the signal that we must go out because the baby elephant has no more oxygen.
In the oceans, whales, the largest animals on the planethave a gestation period of about a year, depending on the species, and up to a year and a half for orcas.
But the world record among mammals belongs to the lizard shark, which measures only two meters as an adult. This species only lives in the depths of the oceans, up to 1,500 meters. It is very cold there and this makes the baby’s growth particularly slow, with a gestation of three and a half years.
An octopus breaks all records
It’s the same phenomenon for an octopus of the abyss, Graneledone boreopacificaoviparous. Due to the intense cold, at depths of 3,000 meters, egg incubation lasts four and a half years – the record for all categories. The female, exhausted, dies just after giving birth. Motherhood is sometimes a sacrifice.
At the other end of the scale is the mouse, with a gestation of only 20 days. The rodent can produce itself after a month and a half, or a new generation every 45 days. This is the reason why scientists like laboratory mice to conduct their research.
The double gestation of marsupials
In the kangaroo, gestation is barely longer than in the mouse: only around thirty days, even though its weight is 500 times greater. But in reality, the development of the little one continues for eight months in its mother’s pouch, a real incubator for the newborn who weighs only one gram at birth – he does not yet have lungs. The female kangaroo has two uteruses, allowing her to carry three babies at different stages of development.
The principle is the same for another marsupial from Australia, much smaller: the quokka, cowardly enough in the face of a predator to expel its young from its pocket and sacrifice it to save its skin. But in his eyes, this is not very serious for the perpetuation of his species, since an embryo is already waiting in his uterus, ready to begin its development.
Question of the week
“Why so many flames in Los Angeles?”
Because it’s been 7 months since it rained, or almost: barely 4 mm since June. The leaves are a fuel as soon as their water content is less than 80%. Faced with flames, trees have armor, their bark, the thickness of which depends on the species and age. A 2 cm bark can withstand fire for ten minutes. And it’s only 45 seconds if it’s half a centimeter long. But it is not fires that threaten forests the most. What kills first is drought, made worse by global warming. In 2022, 36 million trees will die in California from lack of water. A slow death, slowly, but without flame.
