Amazing animal babies giant baby born size of a first-grader! Dad gives birth on ice! Stork brings bundle to two-million-year-old! Plus: shell shocker exposed

Amazing animal babies giant baby born size of a first-grader! Dad gives birth on ice! Stork brings bundle to two-million-year-old! Plus: shell shocker exposed – Life science: reproduction.stump lizards; Emperor penguins; rhinoceros born in captivity

Mona Chiang

GIANT STUMPY

CONTRARY TO popular belief, not all lizards lay eggs. Some are viviparous, or give birth to live young. And when the shingle-back–also known as the stumpy lizard–delivers, it’s a mother load. “Baby stumpies are very large,” says biologist Suzy Munns at Adelaide University in Australia. “They’re approximately 35 percent of the mother’s body weight, which is very high in the animal world.” In other words, if a human were to deliver as hefty a baby, “it would mean giving birth to a child the size of an average 6-year-old!”

More painful yet, unlike humans the pregnant stumpy’s body doesn’t expand to accommodate the developing young–baby just invades mom’s body cavity (see X-rays, right). And the reptile (back-boned animal with scaly skin) can carry up to four babies at a time! Courageous?

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The offspring’s impact on mom’s internal organs exposes her to health risks. During the five to six months of gestation (period of carrying developing young), her lungs and digestive tract become increasingly squashed. In the six to eight weeks before birth, the pregnant stumpy’s frequency and volume of breath reduces dramatically. And by the last four weeks, mom’s metabolism (rate of convening food into energy) drops significantly; she can hardly move or eat, let alone forage for food. More dangerous for mom: She can’t flee predators.

VITAL STATS

SPECIES: SHINGLEBACK “STUMPY” LIZARD (TRACHYDOSAURUS RUGOSUS)

HABITAT: AUSTRALIA

LIFE SPAN: ABOUT 20 YEARS

SIZE: UP TO 41 CENTIMETERS (16 INCHES) LONG

DIET: SNAILS AND OTHER SLOW-MOVING INSECTS, PLANTS, AND FRUITS

FACT: SHINGLEBACKS MATE FOR LIFE. FEMALES GIVE BIRTH ONLY IN SPRING.

DAD DELIVERS

IF MEDALS WERE awarded for childbirth, the father emperor penguin might grab the prize. For nine weeks he stands nearly motionless on Antarctic sea ice, rocking gently to prevent frost from caking his feet. He eats nothing, dropping as much as 50 percent of his body weight–all to incubate (hatch) the egg containing his offspring.

After a 63-day gestation period, a female lays one egg, in late May. Exhausted, she heads off to feed at sea. As the harsh, dark Antarctic winter (March to September) sets in, temperatures plunge to -60 [degrees] C (-76 [degrees] F). The father bird cradles the egg between his legs, covering it with his brood patch (thick roll of skin and feathers). Under the patch, his engorged (filled) blood vessels warm the egg to 36 [degrees] C (96.8 [degrees] F).

More than 130,000 male emperor penguins–in 40 colonies on the icy continent’s fringes–brave this endurance test at a time. Talk about a support group: Without food, drawing fuel from a thick layer of blubber (fat), fathers conserve energy through sleep. But the emperor’s body, with its thick layers of waterproof feathers (80 feathers per square inch), can only insulate without the aid of the body’s energy to withstand temperatures as low as -10 [degrees] C (14 [degrees] F). So as many as 5,000 emperor dads huddle with their backs to the wind to share body heat. Very slowly they shift in a complex serpentine pattern, giving each member equal time at the warmest parts of the inner “circle.”

When mom returns in September to feed her now downy-fluffed chick with regurgitated food, dad takes a six-week feeding break. Both parents raise the chick until the sea ice thaws in January–when chicks begin to fledge (live independently).

VITAL STATS

SPECIES: EMPEROR PENGUIN (APTENODYTES FORSTERI)

HABITAT: ANTARCTICA

LIFE SPAN: ABOUT 20 YEARS

SIZE: 100 TO 130 CM (40 TO 51 IN.) TALL

WEIGHT: 30 TO 38 KG (66 TO 84 LB)

DIET: FISH, SQUID, AND KRILL (SMALL, SHRIMPLIKE ORGANISMS)

FACT: FLEDGLING PENGUINS TAKE TO THE SEA TO EAT AND GROW. WITH NO SURVIVAL TRAINING, FEW LIVE TO REACH ADULTHOOD. SURVIVING OFFSPRING RETURN TO THE COLONY TO BREED IN FIVE OR SIX YEARS.

THE SHELL EXPOSED: DEVELOPMENTAL STAGES OF A CHICKEN A chick’s life begins when a rooster’s sperm (male sex cell) fertilizes an ovum (female reproductive egg) inside a hen to form a single cell called a zygote. The zygote divides and grows into an embryo (developing young). A protective shell forms over the embryo in the hen’s uterus. Chickens are oviparous (hatch outside the body). The hen lays the egg and incubates it, warming the egg to near 37.7 [degrees] C (100 [degrees] F.)

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RARE BUNDLE

SURVIVAL OF newborns becomes even more critical when the race is on to battle extinction. With a staggering 60 percent population decline in the last 10 years, Sumatran rhinoceroses number fewer than 300 today. Believed to have first stomped on Earth 2 million years ago, the mammal (animal that nurses its young) now faces the constant threat of poachers in the forests of Indonesia and Malaysia: its horns are prized for medicine. Despite conservation measures like reserves (protected areas in the wild), the rhino’s count continues to dwindle.

On September 13, 2001, hope arrived in a 33-kilogram (72-pound) bundle: Andalas (on-DA-las) was delivered at Ohio’s Cincinnati Zoo–the first captive birth in 112 years! But raising the captive count to 16 isn’t the boy calf’s only achievement. His rare birth offers scientists unprecedented data on the growth and reproduction of the species.

Emi, Andalas’s mother, had previously miscarried within the first three months in five pregnancies. “Sometimes, when animals miscarry at an early stage, it’s because of a hormone [brain chemical that regulates body functions] deficiency,” says animal reproductive physiologist Terri Roth at the Cincinnati Zoo. During the sixth trial, ultrasound (technology using high-frequency sound waves to map body-organ shapes) detected the pregnancy at 16 days after breeding. So Roth immediately began feeding Emi daily doses of progesterone (hormone essential to pregnancy) injected into bread. Emi fed on the supplement for 465 days. Ten days later, Andalas arrived. “We can’t say if that’s what did it,” Roth says. “But it seems so.”

Perhaps the biggest scientific challenge is to get Sumatran rhinos to breed. In the wild, these rhinos are extremely solitary. Usually, a bull (male) seeks out a cow (female) only when he detects a scent signaling she’s prepared to mate. But when the female isn’t receptive, there can be a lot of aggression among the sexes. Breeding centers established near or in the reserves have yet to produce a successful pregnancy.

As for Emi and Ipuh (Andalas’s father), “the animal managers were afraid to get them together,” says Roth. To gage the right timing, she tried to measure Emi’s hormone levels and ovulation (egg-producing) cycle. “But I never saw her ovulate.” A successful mating revealed this rhino species is an induced ovulator (ovulates only after breeding, rather than on a periodic cycle). “With only one animal to study, we kept questioning if it was a fluke,” Roth explains. But later findings proved similar results.

The zoo estimates Andalas will reach maturity in five years, and it has plans to carefully document the calf’s physical and behavioral growth–including regular plaster casts of his widening hoofs. The data could help rhino census-takers track and protect calves in the wild: Sumatran rhinos are so elusive they’re counted by hoof prints. “It’s exciting,” says Roth. “One birth can change so much about what we know.”

VITAL STATS

SPECIES: SUMATRAN RHINOCEROS (DICERORHINUS SUMATRENSIS)

HABITAT: FORESTS OF INDONESIA AND MALAYSIA

LIFE SPAN: ABOUT 30 YEARS

SIZE: 1 TO 1.5 M (3.3 TO 5 FT) TALL, 2.5 TO 2.8 M (8 TO 9 FT) LONG

WEIGHT: 600 TO 800 KG (1,322 TO 1,763 LB)

DIET: HERBIVORES (PLANT EATERS), THEY FEED ON BRANCHES AND LEAVES.

FACT: THE SMALLEST AND MOST ENDANGERED OF FIVE RHINO SPECIES, IT’S ALSO CALLED THE “HAIRY RHINO” BECAUSE OF ITS SHAGGY BODY.

WATER BABY

Last December, visitors to Busch Gardens Tampa Bay in Florida got a bonus eyeful. They witnessed Cleo, a hippopotamus cow, deliver a girl calf–Moxie–after an eight-month gestation. Most hippo births take place in the water; newborns can swim and nurse underwater immediately. At birth, a calf weighs between 27 to 45 kg (60 to 100 lb). Adult hippos weigh up to 3,175 kg (7,000 lb) and can live for 50 years.

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Cross-Curricular Connection

Conservation: Besides Sumatran rhinoceroses, there are many other endangered species on Earth. Select one animal and report on its threats. What measures are being taken to help protect the species?

Did You Know?

* At 7 weeks old, growing emperor penguin chicks require more nourishment than before. While both parents search for food, chicks congregate in a creche (day care-like environment), protected by a few adults. Parents identify their young by sound.

* Emperor penguins are excellent divers and can plunge deeper than any avian (bird) species. They mostly forage for food at between 150 to 250 meters (492 to 820 feet) deep, lasting 3 to 6 minutes. The deepest dive recorded is 565 m (1,854 ft), the longest dive 22 minutes.

* The Sumatran rhinoceros has two horns. Its favorite activities are sleeping, eating, and playing in mud. Mud cools its body and protects it from insect bites. They’re also excellent swimmers.

Directions: Answer the following questions in complete sentences.

1. What’s the difference between supermarket eggs and those that hatch into chickens?

2. How does the baby stumpy lizard’s large body size affect the mother’s body during gestation?

3. How do father emperor penguins endure the incubation process during the harsh Antarctic winter? Incorporate the following vocabulary words into your answer: brood patch and blubber.

4. What are two reasons the Sumatran rhinoceros population is dwindling?

ANSWERS

Answers will vary but should include the following points and definitions.

1. Supermarket eggs don’t hatch when incubated. They’re not fertilized by a rooster.

2. The pregnant stumpy’s body doesn’t expand in size to accommodate the developing young; therefore, the offspring’s takeover of mom’s body cavity exposes her to health risks. Her lungs get increasingly squashed, causing frequency and volume of breath to reduce dramatically. Also impacted: her digestive tract. By the last four weeks of gestation, mom’s metabolism drops significantly. Hardly able to move, she can barely eat, let alone forage for food. And she can’t escape predators.

3. For nine weeks, the father emperor penguin stands nearly motionless on Antarctic sea ice, rocking gently to prevent frost from caking his feet. He protects the egg containing his offspring by cradling it between his legs. Then he covers it with a thick roll of skin and feathers called brood patch, where the temperature is a warm 36 [degrees] C (96.8 [degrees] F). Without food a penguin dad drops as much as 50 percent of his body weight. He draws energy from blubber (fat) and conserves it through sleep. Emperor dads also huddle with their backs to the wind to share body heat. Very slowly they move in a complex serpentine pattern, giving each member (as many as 5,000) equal time at the warmest parts of the inner circle.

4. The Sumatran rhino in its natural forest habitats of Indonesia and Malaysia lives under constant threat of poachers: Its horns are prized for medicine. It’s also difficult for rhinos to breed. In the wild, they’re extremely solitary. Usually, a bull seeks out a cow only when he detects a scent signaling she’s prepared to mate. But when a female isn’t receptive, there can be a lot of aggression between the sexes. Captive birth proves difficult–Cincinnati Zoo’s Andalas was the first in 112 years. The calf’s mother had previously miscarried five times, all within the first three months of gestation. Scientists believe when animals miscarry at an early stage, it’s because of a hormone deficiency. They’ve also discovered Sumatran rhino cows are induced ovulators–or ovulate only after breeding, rather than on a periodic cycle.

National Science Education Standards

Grades 5-8: reproduction and heredity * structure and function in living systems * regulation and behavior

Grades 9-12: the cell * behavior of organisms * natural and human-induced hazards

Resources

Visit Andalas, Cincinnati Zoo’s baby Sumatran rhino at: www.cinyzoo.org

To learn more about chicken embryology, check out the University of Illinois Chickscope Web site: chickscope.beckman.uiuc.edu/

For more on penguins, visit the International Penguin Conservation’s Web site: www.penguins.ac

COPYRIGHT 2002 Scholastic, Inc.

COPYRIGHT 2002 Gale Group