A zoo in Ohio is celebrating the 'miracle ' birth of three rare Amur tiger cubs after it was feared their mother 's biological clock had stopped ticking . Keepers at the Columbus Zoo say ten-year-old Irisa had mated before but never conceived . However , this spring it was found the female cat was pregnant - with triplets . While the birth on Tuesday morning went smoothly , Irisa failed to show any maternal care so her offspring are currently being hand-reared in an incubator . Scroll down for video . Open wide : A zoo in Ohio is celebrating the 'miracle ' birth of three rare Amur tiger cubs after it was feared their mother 's biological clock had stopped ticking . Bundle of joy : Keepers at the Columbus Zoo say ten-year-old Irisa had bred before but never conceived - however , this spring it was found the female cat was pregnant - with triplets . 'We are always cautiously optimistic about the survival of fragile newborns , ' said Columbus Zoo president Tom Stalf . 'But the cubs seem to be thriving under the 24-hour care provided by our animal specialists and veterinarians . ' Video footage shows the newborn siblings writhing around and napping . The baby cats currently weigh a healthy 2.5lbs but they 're set to grow to a heftier 650lbs . Their eyes are also closed but should open over the coming days . In safe hands : While the birth on Tuesday morning went smoothly , Irisa failed to show any maternal care so her offspring are currently being hand-reared in an incubator . Taking it easy : Video footage shows the newborn siblings writhing around and napping . It is unknown when they will go on display to the public and how keepers will go about naming them . These are the first cubs for ten-year-old female , Irisa , although the Zoo team and the Tiger Species Survival Plan ( SSP ) had hoped for years she would reproduce and pass on her valuable genes . This is the third litter sired by 11-year-old , Foli , since 2012 . Gestation for tigers is about three-and-a-half months which means the cubs were conceived just weeks before Foli left for another facility in Kansas on February 25 . He has been retired from breeding . Tiny tots : They currently weigh 2.5lbs but are set to grow to a heftier 650lbs . Growing pains : Their eyes are also closed but should open over the coming days . Bright futures : It is unknown when they will go on display and how keepers will go about naming them . A new male tiger , Jupiter , arrived at the Columbus Zoo on March 19 . Jupiter was born at the Moscow Zoo in 2007 and came to the Columbus Zoo from the Dvur Kralove Zoo in the Czech Republic . Both males were moved at the recommendation of the Species Survival Plan in an effort to maintain a sustainable population of tigers in human care . With the addition of the three cubs there are currently ten Amur tigers at the Columbus Zoo including four cubs born in 2013 and their mother , Mara .
Keepers at the Columbus Zoo say ten-year-old the Dvur Kralove Zoo had bred before but never conceived . However , this spring it was found the female cat was pregnant . While the birth on Tuesday went smoothly , the Dvur Kralove Zoo failed to show any maternal care so her offspring are being hand-reared in an incubator . They currently weigh 2.5lbs but are set to grow to a heftier 650lbs .