In the latest installment of our occasional conversations with Fort Worth leaders, Kim Rainwater, veterinary services director at the Fort Worth Zoo, and Don Nevitt, manager of the zoo’s elephant breeding program, talk about what it takes to deliver a baby elephant at the zoo.
On Nov. 9, the Fort Worth Zoo announced the birth of Brazos, the fourth calf born at the zoo in addition to his mother Bluebonnet in 1998 and his aunt Belle and half-brother Bowie in 2013. Brazos was born on Oct. 21 weighing 255 pounds and standing 37 inches tall.
This conversation has been edited for length and clarity. For the unabridged version, please listen to the audio file attached to this article.
Cecilia Lenzen: Hi, everyone, this is Cecilia Lenzen, a reporting fellow with the Fort Worth Report. I’m here today to have a conversation with Dr. Kim Rainwater and Don Nevitt from the Fort Worth Zoo.
Let’s start by telling the readers and listeners your job titles, and explain what each of you do in your roles?
Kim Rainwater: So I’m the director of veterinary services. This is Dr. Kim Rainwater, and I lead the veterinary department, which includes — if we’re counting me in the count — three full-time veterinarians, a veterinary intern in a postgraduate training program for veterinary technicians, a procurement keeper and a hospital keeper. So I kind of divide my time up between my administrative role as the director of the department and my clinical role as a practicing veterinarian taking care of all the animals here at the zoo.
Don Nevitt: Hi, I’m Don Nevitt, the elephant curator. I oversee the elephant department. There’s nine full-time staff who take care of the elephants, including me. So we do the daily husbandry and training and all the care of the elephants.
Lenzen: Tell me about the elephant breeding program. How many elephants have been born through the program, and how has it changed throughout the years?
Nevitt: Well, we have eight elephants now. We have two adult males and three adult females and then we have an 8-year-old female. So we monitor their cycles through weekly blood samples so we know when they’re cycling. And then we’ll put the males and females together so we can hopefully have successful breeding. We’ve had four calves born here at the zoo with Brazos being the most recent.
Lenzen: At the Fort Worth Zoo, how many people are involved in each elephant’s pregnancy and delivery?
Rainwater: It’s pretty much all of the elephant department and the vet department, minus our hospital keeper. But there’s a lot of planning and preparation that goes into it. A lot of monitoring all along even when the elephants aren’t pregnant. And then additional monitoring once they do go into their pregnancies. A lot of people are involved.
Nevitt: Yeah, it’s all of the elephant department (and) the nutrition department. We monitor their diets.
Lenzen: Ballpark range, how many people would that be?
Rainwater: So like 11 with vet and nutrition probably.
Nevitt: And then like nine elephant keepers.
Lenzen: OK, so how hands-on is the actual delivery? Does the mother do most of the work herself, or is there a lot of assistance from the staff?
Nevitt: I mean obviously she does most of the work, but we’re there to watch her and make sure everything goes smoothly.
Rainwater: Yeah, it really depends on the situation, but we prefer if it’s possible for the mom to do everything herself. That’s the ideal situation.
Lenzen: So I understand that the Asian elephants can be pregnant for 18 to 22 months. Why the longer pregnancy period?
Rainwater: Well, they’re such a large mammal, and other large mammals also have longer gestations or pregnancy periods. There is a (correlation) in mammals of pregnancy length and brain size. So elephants have to have pretty developed brains when they’re born to be able to survive after birth. And so we think one of the primary reasons they have such a long gestation or pregnancy length is to allow time in the mom for that brain development and other development to happen so that they’re successful after they’re born.
Lenzen: How old was Bluebonnet when she became pregnant with Brazos, and what’s the general age range for when Asian elephants become pregnant?
Nevitt: Well, she was — let’s see, she’s 22 years old now, so she was about 20 years old when she got pregnant. Elephants can start cycling when they’re about seven or eight, so once they start cycling, I mean if there’s a male around, they can become pregnant. They can also breed probably up until they’re around 50.
Lenzen: OK, so kinda similar to humans, just starting a little younger.
Nevitt: Yes, pretty similar.
Lenzen: What does prenatal care look like in the zoo’s elephant breeding program?
Rainwater: So as I mentioned, we do track elephants pretty closely. We do regular exams on them at least once a year with the adults but much more frequently with the juveniles. So the prenatal monitoring is pretty much just an extension of that.
We normally monitor hormones regularly, as Don mentioned before, for the females to track their cycles in order to time breeding appropriately for success. So we continue that monitoring into the pregnancy period where we monitor progesterone, which is a hormone that helps maintain the pregnancy. We monitor that weekly for the majority of the pregnancy, then we monitor it daily as we get close to the end of pregnancy because that really helps us determine when to start watching closer for the impending labor.
Then we also monitor other blood work parameters regularly to make sure that there’s no metabolic or inflammatory or infectious problems that have developed during the pregnancy and make sure the pregnancy is running smoothly.
One of the primary parameters we look at, too, in the bloodwork is calcium. We want to make sure that she has an adequate level of calcium in her body going into the labor. That’s where we collaborate pretty closely with (the nutrition department) as well to make sure the diet is formulated specifically for that individual because it’s not a one-size-fits-all kind of thing. We need that calcium level to be in a desired target range going into the labor because it’s vital for the uterus contractions to happen.
Lenzen: What are some other ways, aside from pregnancy length, that an elephant pregnancy and birth are different from a human pregnancy and birth?
Rainwater: Well, you know they’re a different species, different animal — much larger than humans, but we do a lot of things similarly. We monitor the pregnancy for the duration of it, we do track their blood parameters more than they do with human pregnancies.
We are a little less reliant on specific measurements in the ultrasound, but we still do ultrasounds. Because of where the uterus is initially, we do a transrectal ultrasound for the first 200 to 240 days where we can see the fetus and it’s kind of up in that pelvic canal. And then after that time, in the second half of the second trimester into the third trimester, we can monitor the elephant through ultrasounds through the skin on the belly, and that’s similar to what they do with people.
But we just can’t do as detailed of measurements because of the size of the elephant, the size of the calf. We can see movement, we can see heartbeat, sometimes we can get other certain parameters. Like sometimes we can see the placenta and fluid in the uterus. But as for the more detailed measurement and tracking the exact percentage of growth and everything, we’re not able to be as detailed with that.
So we track the bloodwork a lot closer and look at the progesterone to help us determine when the labor will happen. And that’s a little bit different, too. In people, it’s a pretty defined period of time, and we typically know a smaller window of when somebody’s going to be giving birth. But with the elephants, the window is quite large. Like you said, 18 to 22 months gestation, and it may be even a little over 23 months sometimes. So really big range, and so monitoring the progesterone levels really helps us key in on when that labor might happen. And there’s some other things like behaviors that the elephant staff look for, too.
Lenzen: And what are some of those behaviors that the elephant staff looks for?
Nevitt: You can tell she’ll start being uncomfortable. She might swat her tail on her vulva, and you can see when she has contractions she might start stretching out or kicking her back legs a little bit.
Rainwater: And just one other thing, too, after that when the calf is born, the difference there is they are still quite reliant on their mothers for a long period of time, but they are significantly more precocious than human babies. They can walk around and are just so much more mobile and able to adapt with their environment than human babies are right away.
Lenzen: Obviously like you mentioned, elephants are much, much bigger than humans, so we were curious how many centimeters does an elephant need to dilate to give birth or if that’s something that’s even measured?
Rainwater: Well, it would need to be big enough for the calf to pass, but we don’t really track that. Depending on how long the labor goes, we can do ultrasounds and see where the calf is in the reproductive tract. But we don’t really do the measurement like they do with people.
Lenzen: OK. So how long is an Asian elephant’s delivery, and how long did it take Bluebonnet to deliver Brazos?
Rainwater: So that’s quite variable.
Nevitt: Yeah, that can be a pretty big range. With Bluebonnet, we started seeing contractions about 9:30, then he was born about 11:35, so he was just over two hours. But I’ve seen an elephant birth last 20 minutes, then there’s some of them that have gone over a day.
Rainwater: I think the longest recorded is 90.5 hours, but they can be pretty quick too like (Bluebonnet’s) this time.
Lenzen: Tell me a little bit about Brazos. How big was he when he was born, and how did y’all choose his name?
Nevitt: He was 255 pounds when he was born. He was 37 inches tall, and his trunk was 12 inches. That’s pretty average size for a baby. They’re usually 200 to 300 pounds. And Brazos was chosen because all the elephants have had B names, and they’ve all had something to do with Texas. So we’ve had Bluebonnet, Bluebell, Bowie and then Brazos for the river.
Lenzen: OK, cute. So you’ve mentioned a bit already about how baby elephants aren’t as dependent as human babies, but can you give me more specifics about how dependent they are on their mothers?
Rainwater: Well, (Brazos) can get up and walk around independently, and as he’s explored the exhibit with (Bluebonnet) getting out in sunshine this week, he definitely ventures away from her. But as soon as he hears something, he’s always checking in to see where she is, and he goes back to her so he definitely needs her for comfort. He nurses, so he needs her for all of his nutrition and things like that.
Lenzen: And how old do the elephants have to get before they’re fully independent?
Nevitt: Well, he’ll nurse for probably two to three years at least, and he won’t start eating solid foods til maybe three months. If (Brazos) was a female in the wild, he would be with his mother forever. He’d stay with the herd forever. But a male in the wild would leave the herd around maybe early teenage years. So he’ll be dependent at least till 10 or 11. He’ll be eating on his own and stuff, but he’ll still want to be around her.
Lenzen: And for Fort Worth Zoo visitors who want to see Brazos, will he be available for viewing the same as the other elephants, or will there be specific viewing hours for him?
Nevitt: Right now, he’s out from 11 a.m. to 2 p.m. in the main habitat, and that will be daily. Going into the colder months, 50 degrees is his cut off. But right now it’s 11 to 2.
Lenzen: OK, those are all of my questions, but is there anything else you want the readers and listeners to know about the Asian elephants pregnancy and delivery period?
Rainwater: I think the only other thing we didn’t necessarily touch on is how much planning goes into the elephants’ pregnancy and birth. So we definitely have some detailed protocols in place, especially for the elephant birth to make sure that we’re prepared for all different scenarios that could arise. We have all sorts of supplies packed together so we’re ready to go when the birth does happen, and we have meetings with the vet staff, nutrition staff and elephant staff to just make sure that we’re all prepared for it. It’s something that we take very seriously, and we just want to make sure that it goes as smoothly as possible.
Fort Worth Report fellow Cecilia Lenzen can be reached at email@example.com or via Twitter. At the Fort Worth Report, news decisions are made independently of our board members and financial supporters. Read more about our editorial independence policy here.