This Saturday, Nov. 1, 2014 photo provided by the Los Angeles Zoo shows a mother Hippo and her new-born calf in their enclosure at the Los Angeles Zoo. The Zoo's female hippopotamus, Mara, went into labor on Friday, Oct. 31 and gave birth to a healthy calf. This is the first hippopotamus calf the Zoo has had in 26 years. (AP Photo/Los Angeles Zoo)

The Los Angeles Zoo has received a real treat for Halloween—the birth of its first hippopotamus in 26 years. It was a bit of trick, too, because the mother was on birth control.

The zoo says the baby was born Friday. It was somewhat of a surprise, but staffers had noticed the mother hippo gained weight, which made them suspect she was pregnant.

Vets haven't determined the sex of the new hippo. But they say the baby appears to be doing well and is bonding with mom.

Media will get to see the newborn Tuesday in its .

The mother, 10-year-old Mara, came to the zoo in December from Topeka, Kansas. The father is a 3-year-old named Adhama, who arrived from the San Diego Zoo last year.

This Saturday, Nov. 1, 2014 photo provided by the Los Angeles Zoo shows a mother Hippo and her new-born calf at their enclosure at the Los Angeles Zoo. The Zoo's female hippopotamus, Mara, went into labor on Friday, Oct. 31 and gave birth to a healthy calf. This is the first hippopotamus calf the Zoo has had in 26 years. (AP Photo/Los Angeles Zoo)

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