(COLORADO SPRINGS) — The Cheyenne Mountain Zoo’s (CMZoo) resident heartthrob Omo the hippopotamus has almost reached a milestone! The not-so-little hippo is almost at 1,000 pounds, and the zoo wants everyone to join in the fun and guess when he’ll hit the mark.

CMZoo posted on Facebook on Tuesday, May 2, and said the “growing boy” hit 960 pounds on May 1, after gaining 30 pounds through the month of April. Given the amount of weight he’s gaining, the zoo decided to host a guessing game for when 21-month-old Omo will reach this important milestone.

  • Omo the hippo at CMZoo

The zoo said Omo is weighed “opportunistically,” meaning the zoo doesn’t get a regular weight measurement for him, only when he happens to wander over the scale separately from his 3,100-pound mom, Zambezi.

CMZoo said a “zoo prize” is up for grabs if you guess correctly. You can leave a comment under their Facebook post with your guess for your chance at winning.

“When keepers can weigh him on the big scale in the hippos’ indoor training space and he has hit or surpassed 1,000 pounds, we’ll announce that date and notify our winner,” said the zoo.