SAN FRANCISCO (March 1, 2010) — Every family has its share of extreme characters, and ours is no exception. For evidence, look no further than the newest exhibit at the California Academy of Sciences. Extreme Mammals: The Biggest, Smallest, and Most Amazing Mammals of All Time showcases some of our most intriguing relatives, from the speedy to the sloth-like, the towering to the tiny, even the venomous and the armor-clad. Featuring spectacular fossils and reconstructions alongside recent specimens and live animals, the exhibit explores the surprising and often extraordinary world of extinct and living mammals. A whale that could walk? A bat the size of a bumble bee? Mothers who are pregnant for almost two years… or just 12 days? Extreme Mammals will allow visitors to meet this colorful cast of characters, discover their place in the family tree, and learn why humans are perhaps the most extreme mammals of all. The exhibit opens on April 3, 2010 and runs through September 12, 2010.
During a trip through the world of Extreme Mammals, visitors will learn how mammals evolved, how scientists define this group (would you have guessed one of the defining traits is the ability to eat and breathe at the same time?), and how some of the most extreme adaptations in the mammalian family support survival and reproduction. Highlights of the exhibition include taxidermy specimens—from the egg-laying platypus to the recently extinct Tasmanian wolf—as well as fleshed-out models of spectacular extinct forms, such as Ambulocetus, a “walking whale.” Visitors will encounter the skeletal model of Puijila darwini, a newly discovered extinct "walking seal" from the High Arctic with webbed feet instead of flippers; a life-size model of Indricotherium, the largest land mammal that ever lived; one of the oldest fossilized bats ever found; and an impressive diorama featuring the warm swamps and forests that flourished on Ellesmere Island, located in the High Arctic, about 50 million years ago.
Another mammal featured in the exhibit, Homo sapiens, may look more familiar, but this big-brained, bipedal mammal has evolved several extreme features. “We don’t often think of ourselves as extreme mammals, since we don’t have long horns or venomous spurs,” said Dr. Zeresenay Alemseged, Curator of Anthropology at the California Academy of Sciences. “However, we are without a doubt one of the most extreme mammals that evolution has produced. Our brain-to-body weight ratio is higher than any other mammal on Earth, and our ability to make and use complex tools sets us apart from all other life forms. That trait has enabled us to occupy virtually all parts of our planet and even explore others.” Dr. Alemseged’s research, including his discovery of the oldest and most complete known hominin child, will be featured in a video display in the exhibit.
Extreme Mammals is divided into nine sections: Introduction, What is a Mammal?, What is Extreme?, Head to Tail, Reproduction, Mammals in Motion, Extreme Climates, Extreme Isolation, and Extreme Extinction. Through the use of dynamic media displays, animated computer interactives, hands-on activities, touchable fossils, casts, taxidermy specimens, and a live tree shrew, the exhibition highlights distinctive mammalian qualities and illuminates the shared ancestry that unites these diverse creatures.
- Introduction: Before entering the gallery, visitors will discover models of the largest and smallest land mammals ever found: an overwhelming 15-foot-tall model of Indricotherium, an ancient rhinoceros-relative that was the largest mammal to walk the Earth; and a life-sized model of the extinct shrew-like Batodonoides, the smallest mammal ever documented, which weighed less than a twentieth of an ounce, or the equivalent of a dollar bill. Among living mammals, the awards for biggest and smallest go to the 200-ton blue whale, the largest animal—mammal or otherwise—ever known; and the bumblebee bat, the smallest living mammal, which is literally no bigger than a bee and as light as a dime.
- What is a Mammal?: Before exploring more extremes, visitors are introduced to the basics of mammal evolution and biology. There are more than 5,400 mammal species alive today, classified into 20 different groups, called orders. About 300 million years ago, the evolutionary branch of the tree of life that includes mammals split off from the branch containing reptiles. For over 130 million years, mammals lived side by side with dinosaurs. Some early mammal relatives have even been mistaken for dinosaurs, such as the sail-back synapsid Dimetrodon, a fossil featured in this section. The fossilized skull of the more mammal-like Cynognathus shows the specialized teeth of early mammal ancestors, but not all the characteristics of the living groups of mammals. To be classified as a mammal, a species must also nurse their young with milk; have three middle-ear bones; use a diaphragm for breathing; have a secondary palate that allows simultaneous eating and breathing; and maintain a warm, stable body temperature.
- What is Extreme?: The skeleton of an opossum and a cast of a human skeleton illustrate a range of combinations of "normal" and "extreme" mammalian qualities. While many opossum features are normal for mammals, like body size, the Virginia opossum's prehensile tail, which it uses like an extra limb to grasp or hang from branches is an exceptional feature. Humans are out of the ordinary with their large brain-to-body ratio and the ability to walk upright on two legs. There are a few other bipedal mammals, but they are mostly hoppers like kangaroos. Humans also have some normal features compared to other mammals, such as three middle ear bones and five digits on each hand and foot.
- Head to Tail: Horns, tusks, noses, brains, body armor, and tails have come a long way in the evolutionary history of mammals. The purposes of these traits may include self-defense, recognizing kin, or attracting mates. For example, the Indonesian babirusa pig uses teeth that grow through the bones and skin of the top of its snout for display and fighting. The complete fossil skeleton of a glyptodont shows how this car-sized armadillo-relative was covered with a thick, bony shell, or carapace, to protect itself from large predators. The life-sized model of Macrauchenia features a camel-like body, giraffe-like neck, and elephant-trunk-like nose. While a specimen with a preserved nose has never been found—Macrauchenia went extinct 10,000 years ago—the reconstruction of its unusual trunk is based on skull features found in mammals with similar specialized noses and a comparison of early and later members of the same group.
- Reproduction: Giving birth to live, well-developed offspring is “normal” for most mammals, but more than 300 species of living extreme mammals do things differently. Monotremes (mammals that lay eggs) and marsupials (mammals that give birth to very immature offspring and often have pouches) are each extraordinary when it comes to reproduction and far removed from the more common placental mammals, which have babies that develop for a long period within the womb. Just a handful of mammals lay eggs, including the platypus and echidnas featured in this section. However, egg-laying is the norm in other vertebrate groups like birds, reptiles, and amphibians. This section of the exhibit is also home to a live tree shrew (Tupaia belangeri), a species that has evolved an unusual system of maternal care. After giving birth to tiny, blind babies, mother tree shrews spend only 25 minutes with their young during the first four weeks of their life. Most likely an anti-predator adaptation, this strategy minimizes the risk that a predator will follow the mother back to her nest. Once the young leave the nest, the mother becomes a more doting parent.
- Mammals in Motion: Whether they move around on land, in water, or by air, mammals have developed amazing features to get from one place to another. The skeleton of the Glossotherium myloides, an extinct ground sloth from South America that was a slow-moving knuckle walker, shows how gigantic these mammals could grow to be. About 50 million years ago, some groups of mammals began to shift from land to ocean life. A life-size relief model of Ambulocetus natans, the extinct “walking whale,” vividly depicts a transitional form between modern-day whales and their extinct land-dwelling ancestors. The cast of the skull and partial skeleton of Puijila darwini, or “walking seal,” has otter-like limbs and a seal-like head. Discovered in the High Arctic in 2007, scientists have described Puijila darwini as another example of a transitional fossil—a missing link in the evolution of pinnipeds, the group that includes today’s seals, sea lions, and walruses. A few mammals glide through the air, such as lemurs and squirrels, but only bats can truly fly. Onychonycteris finneyi, a spectacular 52-million-year-old bat fossil on display, represents the most primitive bat species known to date and demonstrates that these animals evolved the ability to fly before they could echolocate, or detect objects by emitting sounds and gauging their reflections. Of the more than 5,400 species of mammals that exist today, over 1,100 are bats.
- Extreme Climates: A large-scale, intricately detailed diorama of Ellesmere Island, located 600 miles from the North Pole, provides an insightful glimpse of this area 50 million years ago. At that time, the Earth was significantly warmer and Ellesmere Island was covered mostly with forests. This reconstruction shows a warm, humid, and swamp-like forest, vastly different from the bitter-cold Arctic of today, which was home to a variety of mammals. Among the models of extinct mammals in the diorama are Vulpavus, a carnivore with a long, thin body and tail that were well suited for quick movements both in trees and on the ground; Coryphodon, a short-tusked hippo-like wader; and Thuliadanta, an extinct tapir that had a flexible, trunk-like snout. In contrast to the lush vegetation and diverse mammals 50 million years ago, today’s Ellesmere Island is home to plants that are only a few inches tall and fewer than a dozen species of land mammals, including musk ox, caribou, polar bear, and arctic hare.
- Extreme Isolation: Madagascar, Australia, and South America existed as isolated islands and continents for tens of millions of years, leading to the evolution of an incredible diversity of mammals found nowhere else on Earth. Impressive fossils of the extinct hoofed plant-eaters Scarrittia and Astrapotherium illustrate the concept of convergent evolution, the appearance of similar features in distantly related organisms living in similar environments. While Scarrittia looked like a rhino or horse, it was not closely related to either. Astrapotherium developed large tusks and a long trunk, but was not closely related to elephants found on other continents.
- Extreme Extinction: Mass extinctions, or the rapid loss of a great number of species, have happened at least five times over the past 500 million years, and a sixth appears to be occurring today. Climate change, hunting by humans, a crashing comet, and the introduction of new diseases are some of the drivers that may have been behind the permanent disappearance of many large mammalian species about 12,000 years ago. Today, human-caused environmental changes and habitat loss threaten more species. The remarkable fossil skulls and skeletons of Smilodon fatalis, a massive saber-toothed cat, and Canis dirus, the dire wolf, are on display in this area. Both species roamed North America and died out at the end of the last Ice Age. A taxidermy specimen of one of the last-known Tasmanian wolves (also known as Tasmanian tigers) is also on view. After intense hunting, the species went completely extinct as recently as the mid-1930s. Remarkably, even with 25 percent of living species of mammals on the brink of extinction, scientists are still discovering new species. In 2008, Academy research associate Galen Rathbun discovered a new species of sengi that lives only in two high-altitude forest blocks in the mountains of Tanzania—a study skull of this rare animal is on display in the exhibit. Sengis are monogamous mammals found only in Africa that have a colorful history of misunderstood ancestry. Like shrews, these small, furry mammals eat mostly insects. Early scientists named them elephant-shrews not because they thought the animals were related to elephants but because of their long, flexible snouts. Ironically, recent molecular research has shown that they are actually more closely related to elephants than to shrews. Members of a supercohort called Afrotheria that evolved in Africa over 100 million years ago, their relatives include elephants, sea cows, and the aardvark. “This is one of the most exciting discoveries of my career,” said Rathbun, who has studied the ecology, social structure, and evolution of sengis for more than 30 years. “It is the first new species of giant sengi to be discovered in more than 126 years. From the moment I first lifted one of the animals into our photography tent, I knew it must be a new species—not just because of its distinct coloring, but because it was so heavy!” The new species, which has been named the grey-faced sengi (Rhynchocyon udzungwensis), weighs about 700 grams (1.5 pounds), which is more than 25 percent larger than any other known sengi.
Mammals aren’t the only animals with extreme adaptations. For the duration of the Extreme Mammals exhibit, special signage will call attention to extreme features and behaviors of other specimens and live animals throughout the California Academy of Sciences. For example, in the museum’s Rainforests of the World exhibit, the green anaconda is called out as the heaviest snake species, and in the Northern California Coast exhibit, the giant Pacific octopus is identified as the smartest invertebrate.
Special Programs & Activities
- NightLife gets “Extreme” during April (Ages 21+)
Thursdays from 6:00 to 10:00 pm
In April, NightLife gets “extreme” in celebration of the opening of Extreme Mammals. The exhibit will be open during NightLife beginning April 8, 2010. Every Thursday night, the Academy opens its doors from 6-10 pm for NightLife, a chance for adults ages 21+ to explore the museum in a whole new light, with DJs, bars, and provocative science programming. A valid ID is required for entry. Admission is $12 per person ($10 Academy members). California Academy of Sciences, 55 Music Concourse Drive, Golden Gate Park. (415) 379-8000. www.calacademy.org/nightlife.
- April 1, 2010 - “Extremely Jurassic”: This week, NightLife explores the world that dinosaurs lived in with paleontologist Scott Sampson. Music by DJ Miles. Note: Extreme Mammals is open during NightLife starting April 8.
- April 8, 2010 - “Extremely Cosmic”: Join NightLife and NASA for Yuri’s night, a celebration of the anniversary of the first man in space. We’ll also feature the technology of tomorrow with ‘Extreme Robots’ and the music of the SpaceCowboys.
- April 15, 2010 - “Extremely Warm-Blooded”: Extreme mammals come in all shapes and sizes. As a special treat, come see the world’s fastest land animal, a live cheetah, and other amazing big cats.
- April 22, 2010 - “Extremely Green”: On Earth Day, NightLife celebrates our extreme home, Earth, the only planet currently know to support life. Activities include Green Games in African Hall, interactive stations with PG&E about solar panels, and a film by KQED’s QUEST about Earth Day. Michael Anthony of supperclub will be the DJ, with live instrumental accompaniment.
- April 29, 2010 - “Extremely Toothy”: Join acclaimed shark expert and Academy curator John McCosker, and KQED’s QUEST to learn about one of the most feared oceanic predators around: the Great White Shark. Music by White Girl Lust.
- Mammals and Climate Change
Lecture by Dr. Elizabeth Hadly, Department of Biology, Stanford University
Tuesday May 18th 7:00 pm
Dr. Hadly’s research across the globe—from India to Patagonia to Southeast Asia—seeks to answer questions about what determines and maintains vertebrate (especially mammal) diversity through space and time, and examines how that diversity is influenced by the environment. Tickets are $12 adults, $10 seniors, Academy Members Free. Seating is limited and admission is for the lecture only. Purchase advance tickets at www.calacademy.org/event_tickets/index.php, or call 800-794-7576.
- Extreme-themed Family Programs
Learn about a range of extreme creatures during special editions of popular family-friendly programs from April 4– September 12, 2010. The full weekly program schedule is available at www.calacademy.org/events/, and highlights include:
- Specimen Spotlight
Every Friday at 11:30 am
“Extreme” on 1st Friday of the month
Find out more about a different specimen each week in these mini-presentations at the Naturalist Center. The first Friday of each month will highlight an "extreme" specimen. Free with Academy admission. Located in the Naturalist Center.
- Family Nature Crafts (Ages 4-8)
Every Sunday 11 am – 12:30 pm
“Extreme” on 1st Sunday of the month
Families with children aged 4 to 8 are invited to make nature themed crafts. “Extreme-themed” nature crafts are offered on the first Sunday of the month. Free with Academy admission. Space is limited; check lobby for location.
- Science Story Adventures (Ages 6-10)
Every Sunday at 2:30pm
“Extreme” on 2nd Sunday of the month
Explore the natural world through stories, experiments, games and crafts. The second Sunday of the month will feature extreme animals, plants or science on a rotating basis. Free with Academy admission. Space will be filled on a first-come, first-served basis. Located in the Education Classroom.
- Extreme Life Scavenger Hunt: coming to the Naturalist Center in summer 2010.
was organized by the American Museum of Natural History in New York (www.amnh.org), in collaboration with the California Academy of Sciences, the Cleveland Museum of Natural History, and the Canadian Museum of Nature.