Category — Cats
Many visitors to the Zoo have met our two African lions, John and Imani, in the new Africa exhibit. These two young cats were paired up earlier this year with the hope that they would breed and produce their first litter of cubs in the near future. The good news is that breeding activity has been observed on several occasions this past year, and, after at least one pseudopregnancy, it appears that Imani is now pregnant and due to give birth within the next month. Which raises the question – how do you diagnose pregnancy in a lion anyway?
Scientists at the Zoo’s Center for Conservation and Research of Endangered Wildlife (CREW) commonly use three methods for pregnancy diagnosis in wildlife species: ultrasonography, fecal progesterone analysis, and urine relaxin analysis. Ultrasonography remains the gold standard since visualization of a fetus with a strong heartbeat is the definitive proof of pregnancy. CREW frequently uses abdominal ultrasonography to diagnose and monitor pregnancies in our domestic cats (see below). However, this method can be challenging to apply with a potentially dangerous carnivore, like Imani. Through the Zoo’s operant conditioning program, Imani eventually may be trained to allow voluntary abdominal ultrasound exams, but this method is currently not an option with her.
The second approach for pregnancy diagnosis is the use of fecal progesterone analysis. Lions, like other felids, show an increase in fecal progesterone levels shortly after ovulation that is detectable using CREW’s hormone assays. If lions ovulate but don’t conceive, they will have a pseudopregnancy that lasts 50 to 60 days and then progesterone will decline back to baseline levels. If progesterone concentrations stay elevated beyond 60 days post-breeding, then the female is most likely pregnant. Imani’s fecal hormone profile (below) shows progesterone levels increasing coincident with her last breeding activity and staying elevated through at least 66 days post-breeding (the last fecal sample tested).
The third option for pregnancy diagnosis involves measurement of another hormone, relaxin, that is produced by the placenta and excreted in the urine. CREW has helped to pioneer the use of a bench-top relaxin test for pregnancy diagnosis with urine from cats. Our previous research has found that pregnant domestic cats and Pallas’ cats produce high levels of urinary relaxin that are detectable with the bench-top test, but pregnant cheetahs and clouded leopards apparently do not. Imani is the first lion that we have evaluated late in a suspected pregnancy. Urine samples collected from Imani at day 73 and 74 post-breeding were both positive for relaxin (below, circled line in window #2), providing further presumptive evidence of an ongoing pregnancy. In the absence of a sonogram showing a viable fetus, the positive results from the progesterone and relaxin assays provide our best evidence that Imani is pregnant.
Hopefully, Imani will confirm our diagnosis in the next few weeks with the anticipated birth of her first litter of cubs. Since Imani will be a first-time mom, she will be provided with a quiet, off-exhibit den area to give birth and bond with her cubs, and likely will remain off-exhibit until early spring when the cubs are a bit older.
October 28, 2014 No Comments
If you’ve seen our 3 year-old female lioness Imani on exhibit lately, you may have noticed that she’s getting a little round around the middle. But Imani isn’t just packing on the pounds for winter, there is a chance that she might be pregnant!
John and Imani came to the Cincinnati Zoo back in 2012 with a breeding recommendation from the African lion SSP (species survival plan). The SSP helps zoos to work cooperatively to manage captive animal populations so that we can avoid in-breeding and maintain healthy genetics within our captive populations. Fortunately for Cincinnati, John and Imani were matched up and brought to the Queen City to start a pride together.
You can read more about John and Imani’s first meeting here:
Almost immediately after being introduced to each other, keepers began to see breeding behaviors! Since John and Imani are both young, inexperienced lions, the initial breedings didn’t seem to amount to much. More often than not, Imani would only sit still for John for about 20 seconds, then she would swing around and smack him in the face while snarling. Poor John was receiving some very mixed and confusing signals, and breeding Imani seemed like a very daunting and scary proposition. He stuck with it though, and soon the breeding behaviors began to look more (re)productive!
A little bit of background info on lion breeding. Typically, female lions cycle every 17 days, and they are induced ovulators (meaning they only ovulate, or release eggs, when mating has occurred). Induced ovulation helps ensure that breeding is successful because eggs are not being released and wasted unless breeding (and the possibility of fertilization) has occurred.
Keepers were seeing pretty regular estrus cycles from Imani every 17 days or so for the first few months that the lions were together. At each cycle, we observed breeding from the lions. Then, at the beginning of August, we anticipated an estrus cycle that never came. Since that time, keepers have been collecting and submitting fecal samples from Imani to our research department over at CREW (the zoo’s center for Conservation and Research of Endangered Wildlife). CREW analyzed the progesterone levels in Imani’s feces to help us determine that ovulation HAD occurred during the last observed breeding cycles. Even more exciting, Imani’s elevated progesterone levels were a good indication that she might be pregnant!
Now before we start planning a baby shower or registering for baby gifts, we should note another important and fascinating aspect of lion reproduction: pseudopregnancy. Pseudopregnancy (or “false” pregnancy) can cause the female’s body to exhibit signs and symptoms of pregnancy even if she’s not actually pregnant. For this reason, we are not saying “Imani’s pregnant!”. Instead, we are saying “Imani might be pregnant!” We will only know if there has been a true pregnancy if and when Imani delivers her cub(s) sometime this November.
In preparation for possible cubs, keepers have been working around the clock to ensure that Imani has a safe, secure and comfortable place to give birth. We are setting up a special “denning area” complete with full privacy, a cozy nest area, and even video surveillance cameras so that keepers can monitor Imani from a distance. Since Imani will be a first time mom, much of the decision-making that happens from this point on will be based on Imani’s comfort level. Maintaining a sense of security and comfort for her during this pivotal and exciting time is our top priority! We ask for your patience and understanding as one (or both) lions may be spending less time on exhibit during the next month or so leading up to the possible arrival of cubs. As always, thank you for the amazing love and support you’ve shown our lions so far and stay tuned to learn if and when we add new lion cubs to our Cincinnati pride!
Cincinnati Zoo & Botanical Garden
October 28, 2014 3 Comments
You probably already know that the Cincinnati Zoo is committed to the conservation of lions, tigers and cheetahs, but did you know that we are also leading the way in small cat conservation? And our Small Cat Signature Project just got bigger! Our Center for Conservation and Research of Endangered Wildlife (CREW) recently received a Museums for America Grant from the Institute of Museum and Library Services to improve our ability to maintain healthy captive populations of five small cat species across the country—the Brazilian ocelot, the Pallas’ cat, the black-footed cat, the Arabian sand cat and the fishing cat.
Unfortunately, none of these small cat populations are considered sustainable through natural breeding alone. That’s where Dr. Bill Swanson, CREW’s Director of Animal Research and the world’s leading expert on small cat reproduction, comes in. Working in partnership with Dr. Jason Herrick of the National Foundation for Fertility Research and the Species Survival Plan coordinators for each species, Dr. Swanson will direct the project with a focus on three goals: 1) Collect and freeze semen from the most valuable cats for each species, 2) Produce viable offspring using artificial insemination in recommended breeding pairs that fail to reproduce naturally, 3) Produce offspring with frozen-thawed semen from genetically valuable or under-represented males.
Building on CREW’s decades of ground-breaking research on small cat reproduction, successful completion of this project will greatly enhance the sustainability and stewardship of small cat collections in AZA zoos. Now that’s big news!
October 9, 2014 1 Comment