mammals

[icebread]

Are there any mammals that never have more than one baby at a time for a reason? Thank you for your time.

[boxtops]

Some only give birth when conditions are right

[Clanad]

Although there are always exceptions to the rule, most of the large whales never have twins... Same applies to sea lions and it's quite rare for seals to have multiple births.

Seems to have something to do with their environment...

[jomifl]

Elephants?

[jomifl]

Correction ..first male elephant twins in captivity born recently

[Graham-W]

Kangaroos and other marsupials. As far as I know they only have one nipple so twins would be rather complicated.

[heathfield]

Many lemurs. give birth to only one infant. This is an advantage since the infant needs room to cling to the mother for several months. Also, more than one would slow the mother down in trying to avoid predators.

[wildwood]

I don't believe that that are any mammals that NEVER have more than one young. Many of the bigger ones mostly have one at the time and when twins are born it is unlikely for the smallest to survive, but it has happened.

The closest ones that come to 'single young' are some of the armadillo species that always have only one single zygote formation after mating, but that is designed to split in about four so all the young in one gestation are always identical.