ELI5: Explain Like I'm 5

Lactation

Lactation is when mommy animals make milk for their baby animals to drink.

When mommy animals give birth, they have special glands in their breasts called mammary glands. These glands are like factories that make milk. The milk is important for baby animals as it has all the nutrients and vitamins they need to grow strong and healthy.

When baby animals suck on mommy animals' nipples, they get the milk. The nipple is like a straw that the baby animal uses to suck milk out of the mammary gland. The milk flows from the gland through the nipple and into the baby's mouth.

Mommy animals' bodies make milk all the time when they have babies. It is also possible for mommy animals to make milk even if they don't have babies. But this usually happens after a lot of stimulation, like nipple stimulation or taking certain medication.

So in short, lactation is when mommy animals make milk naturally for their babies to drink so that they can grow up big and strong.