The Saint Louis Zoo, Missouri Department of Conservation (MDC) and U.S. Fish and Wildlife Service (FWS) are celebrating a historic milestone in hellbender conservation in Missouri. As of August 2022, the total Saint Louis Zoo-raised endangered Ozark and eastern hellbenders released into the wild since 2008 now numbers over 10,000 individuals.
“This is the largest number of animals the Saint Louis Zoo has ever raised in human care and released to the wild and is one of the largest amphibian reintroduction programs in the world,” said Justin Elden, Curator of Herpetology, Saint Louis Zoo, and Director of the Saint Louis Zoo WildCare Institute Ron and Karen Goellner Center for Hellbender Conservation. “To date, this is the most successful hellbender release program in the country and it would not be possible without collaborative efforts between the Zoo, MDC and other partners over the last 15 years.”
“When we began the hellbender conservation program over 20 years ago the idea of returning this many hellbenders into native rivers was a dream goal and almost impossible to imagine at the time,” said Jeff Briggler, Ph.D., MDC State Herpetologist. “It has been a lot of hard work and dedication from many people and partner conservation organizations, and while we recognize the significance of this milestone, the work is far from over. We will continue to help protect this species from extinction.”
The 10,000th hellbender, which was one of 235 hellbenders released into a Missouri Ozark river on August 10, 2022, by MDC and Zoo team members, was a nearly 4-year-old Ozark hellbender. This hellbender was returned to the same river where it was collected as an egg in 2018 by MDC to be hatched and raised at the Zoo.
“This particular river means a lot to those of us involved in the conservation of this species, as it’s the same river where the first release occurred in 2008,” said Briggler. River locations are not identified for animal safety reasons.
By the end of summer 2022, 811 Ozark and eastern hellbenders raised from eggs at the Zoo will have been released into their native Missouri Ozark rivers by MDC this year, in cooperation with the Zoo and other federal partners.
Since 2008, 10,206 Saint Louis Zoo-raised endangered hellbenders (9,034 Ozark hellbenders and 1,172 eastern hellbenders), including first- and second-generation Zoo-bred animals, have been reintroduced to the wild in Missouri.
“Our Zoo animal care professionals are dedicated to caring for this endangered salamander and doing everything we can to help preserve this species,” said Elden.
Hellbender Breeding & Conservation
The Saint Louis Zoo WildCare Institute Ron and Karen Goellner Center for Hellbender Conservation is a Saint Louis Zoo-based effort aimed at conserving native hellbender populations in Missouri.
Over 1,000 Ozark and eastern hellbenders hatched at the Zoo in 2021.
The hellbender propagation facilities at the Zoo include two large outdoor streams that currently house breeding groups of Ozark hellbenders hatched at the Zoo in 2011. The streams have natural gravel, large rocks for hiding and artificial nest boxes for egg laying. A nearby building houses state-of-the-art life support equipment used to filter the water and maintain the streams at the proper temperature. In addition, four quarantined, climate-controlled rooms behind the scenes of the Charles H. Hoessle Herpetarium at the Zoo are the headquarters for the program.
The facilities recreate hellbender habitat with closely monitored temperatures, pumps to maintain highly oxygenated water, and filtration systems to provide specific water quality parameters. The largest room includes a 32-foot simulated stream and houses a breeding group of adult eastern hellbenders.
The animal care team meticulously cares for these animals and systems. The Zoo’s Life Support Systems team plays a critical role in constructing and maintaining these systems that provide the ideal habitat for the hellbenders at the Zoo.
In addition to the breeding efforts, the Zoo also has been head-starting juvenile Ozark and eastern hellbenders, hatched from eggs collected in the wild, for future release. Currently, the Zoo is caring for around 1,534 hellbenders.
About Hellbenders — An Endangered Species
The official endangered species of the state of Missouri, hellbenders are the largest aquatic salamanders in North America. Missouri is the only state that has both subspecies — the Ozark hellbender (Cryptobranchus alleganiensis bishopi) and the eastern hellbender (Cryptobranchus alleganiensis alleganiensis). Both are listed as state and federally endangered in Missouri.
Both Ozark and eastern hellbender populations in Missouri have declined more than 70 percent over the past 40 years. A population assessment indicated that all hellbender populations have a high risk of extinction (above 96%) over the next 75 years, unless populations are bolstered. Based upon these results, zoo propagation and head-starting were deemed essential to the long-term recovery of hellbenders in Missouri.
The Ozark hellbender can reach lengths up to 20 inches. Also known by the colloquial names of “snot otter” and “old lasagna sides,” the adult hellbender is one of the largest species of salamanders in North America, with its closest relatives being the giant salamanders of China and Japan. It has a restricted range and is only found in the cold-water rivers of south-central Missouri and adjacent north-central Arkansas. Hellbenders have broad flat heads, small lidless eyes and pronounced skin folds on the sides of their body. They can live 25+ years, and their diet includes crayfish, fish, worms and snails. Large rocks on the river bottom provide refuge and nesting sites.
In late summer and early fall, a male hellbender establishes a nest site under a large rock or within a rocky crevice and waits for a female to enter and deposit her eggs to be fertilized. The male defends its nest until the eggs hatch and resulting larvae depart the nest chamber months later.
About the Partners
Home to over 14,000 animals, representing nearly 500 species, the Saint Louis Zoo is recognized worldwide for its innovative approaches to animal care and management, wildlife conservation, research, and education. One of the few free zoos in the nation, the Saint Louis Zoo attracts approximately 3 million visitors annually and is the most-visited attraction in the region. Accredited by the Association of Zoos and Aquariums (AZA), the Saint Louis Zoo is part of an elite group of institutions that meet the highest standards in animal care as well as provide fun, safe and educational family experiences. The Saint Louis Zoo and the other AZA-accredited institutions collectively dedicate millions of dollars annually to support scientific research, conservation and education programs. For more information, visitstlzoo.org.
The Missouri Department of Conservation protects and manages the fish, forest and wildlife resources of the state of Missouri. The state agency facilitates citizens’ participation in resource management, sustainable fishing and hunting, and provides opportunities to experience, enjoy and learn about nature. For more information, visit www.mdc.mo.gov.
The mission of the U.S. Fish & Wildlife Service is to work with others to conserve, protect and enhance fish, wildlife, and plants and their habitats for the continuing benefit of the American people. For more information, visit fws.gov.
Additional conservation partners that have contributed to this conservation propagation program includeU.S. Forest Service, National Park Service, Arkansas Game and Fish Commission, and numerous universities over the years, such as Missouri State University, Missouri University of Science and Technology, and University of Missouri.