LOS ANGELES (CBSLA.com) — The Los Angeles Zoo received a treat on Halloween, the first it has had in 26 years – the birth of a hippopotamus calf.

The calf, which spent the weekend bonding with its mother, Mara, appears to be doing well, Los Angeles Zoo officials said Monday. Zoo animal care staff hope to determine the sex of the baby when they separate it from its mother for the calf’s first check-up.

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Zoo officials say the birth was somewhat of a surprise, though it was not unexpected. Ten-year-old Mara arrived at the L.A. Zoo from the Topeka Zoo in December 2013 to be a companion for the resident male, 3-year-old Adhama, who came from the San Diego Zoo in June 2013.

Mara was on birth control, but Mara’s symptoms – such as weight gain – made animal care staff suspect a birth was imminent, zoo officials said. Without being able to test Mara to confirm their suspicions, staff referenced their breeding notes and guessed that a birth could potentially happen in mid-November after a gestational period of eight months, officials said.

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The healthy calf was born about two and a half hours after Mara went into labor at 1 p.m. on Friday.

Mother, father and baby can all be seen at the L.A. Zoo daily.

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Mom and Baby hippo. (credit: Tad Motoyama/LA Zoo)

Mom and Baby hippo. (credit: Tad Motoyama/LA Zoo)