The trio of elephants at the Toronto Zoo won't be leaving town this summer.

The organization tasked with transporting them to a California sanctuary says the summer heat is too much.

"We're in the middle of a heat wave and because the crates are made of steel and there's some radiant heat potentially. Although the aircraft itself is temperature controlled, you know when the animals are on the tarmac and there's clearance and so on that has to go on, just for safety sake we've decided that we're going to look at September," said Julie Woodyer of Zoocheck Canada.

The original date to ship Iringa, Toka and Thika south was set for Aug. 2.

Animal rights activist Bob Barker has offered to pay for the transportation.

With specialized crates, a team of vets and experts, and the use of a large Russian aircraft, the trip has an estimated price tag of $1 million.

View our gallery of Toronto Zoo Elephants provided by PAWS/Zoocheck Canada

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  • In this image taken on April 5, 2011 provided by PAWS/Zoocheck Canada, an African elephant, Toka, age 41, is shown in the Toronto Zoo in Toronto, Canada. Toka is being retired from the zoo after 37 years, and will be flown on Aug. 2, 2012 to PAWS' 2,300-acre sanctuary in San Andreas, Calif. (AP Photo/PAWS/Zoocheck Canada, Jo-Anne McArthur)

  • In this image taken on November 14, 2011 provided by PAWS, an African elephant, Mara, 28, originally from San Jose's Happy Hollow Zoo, wanders in a field at PAWS ARK 2000 sanctuary in San Andreas, Calif. She will soon meet three other African elephants retiring from the Toronto Zoo who arrive at the preserve on Aug. 2, 2012. (AP Photo/PAWS, Lisa Jeffries)

  • In this image taken on November 14, 2011 provided by PAWS, an African elephant, Lulu, 47, originally from the San Francisco Zoo, roams at PAWS ARK 2000 sanctuary in San Andreas, Calif. Three African elephants from the Toronto Zoo will join her and other animals this summer at the preserve. (AP Photo/PAWS, Lisa Jeffries)

  • In this image taken on April 5, 2011 provided by PAWS/Zoocheck Canada, an African elephant, Iringa, 42, is shown in the Toronto Zoo in Toronto, Canada. Iringa is being retired from the zoo after 37 years, and will be flown on Aug. 2, 2012 to PAWS' 2,300-acre sanctuary in San Andreas, Calif. (AP Photo/PAWS/Zoocheck Canada, Jo-Anne McArthur)

  • In this image taken on May 14, 2012 provided by PAWS, an African elephant named Iringa, 42, is shown in a cage being trained for transport this summer from the Toronto Zoo to a new sanctuary in San Andreas, Calif. Former game show host and animal activist, Bob Barker, is paying the bill to ship Iringa, and two other retiring elephants from the Toronto Zoo, expected to cost between $750,000 and $1 million. (AP Photo/PAWS, Margaret Whittaker)

  • In this image taken on July 10, 2012 provided by PAWS, the African habitat where three African elephants, Iringa, 42, Toka, 41, and Thika, 31, will soon reside is shown at PAWS ARK 2000 sanctuary in San Andreas, Calif. African elephants who live to 60 or 70 in the wild, do not survive well past 50 in captivity. (AP Photo/PAWS, Lisa Jeffries)

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