The Brookfield Zoo in suburban Chicago announced the birth of a male dolphin calf to its 31-year-old dolphin Tapeko.

Dolphin experts at the zoo say they are "cautiously optimistic" about the health of the 40-pound calf, which has shown several signs of good health.

The first 30 days of a dolphin's life are critical, and a number of things could lead to a fatal turn. More dolphins are lost in the first month of life -- both in captivity and in the wild -- compared to any other time, the Brookfield Zoo said in a statement.

The 3.5 foot long calf, which remains unnamed, was born Wednesday, Oct. 16. Following its birth, the calf exhibited several key development milestones, including nursing and slipstreaming, where the calf glides through the hydrodynamic wake created by its mother.

Tapeko and the new calf are currently in an enclosure out of public view to allow them time to bond, the Chicago Tribune reported.

In August, Allie, the zoo's 26-year-old dolphin, gave birth to a calf. The event was captured on video and widely disseminated on the Internet. However, one week after the birth -- and just a day after the video was released and media were allowed in to see -- the calf died. The calf stopped nursing during the night and its health took a rapid turn toward the worse.

"We know that the first 30 days are extremely critical in the calf's life," said Rita Stacey, marine mammal curator for the Chicago Zoological Society, which manages the Brookfield Zoo.

At the time Allie gave birth, Tapeko was pregnant and the zoo said it expected her to give birth this fall.

There is still one pregnant dolphin at the zoo, 11-year-old Spree. She is expected to give birth to her first calf later this fall.

"This is an important time for our breeding group of females," Stacey added. "As an experienced mom, Tapeko is able to demonstrate to the younger females how to care for a newborn calf."

Bottlenose dolphins typically gestate for 12 months, with females reproducing every two to six years.