Memphis Zoo scientists have contributed new knowledge and techniques to the field of conservation biology. Did you know that biologists can now freeze and then reanimate the sperm of many more species than in the past due to the work of Memphis Zoo scientists? Our breakthrough discoveries are the result of precise laboratory experimentation, applying the scientific method. All of our work, no matter how esoteric it might appear, is conducted with an eye toward gaining an important insight or tool which we then put to work to protect animals.
Snakes in the City:
Copperhead surgery to implant a radio-transmitter that allows for tracking of the wild snake. Snakes are held for a of couple days post-surgery for recovery before being released to the field.
Assistant Curator Chris Baker with the largest copperhead found in Overton Park – 40 inches! Chris is holding this magnificent snake while it is safely restrained in a tube.
By tracking copperheads using radio-telemetry, many rarely seen behaviors have been documented, such as this pair in the act of breeding.
Memphians enjoying Overton Park are often in very close proximity to copperheads, yet bites are almost unknown. Copperheads are shy and nonaggressive.
Digging for Insights into Primitive Spiders:
● Animal: Purseweb spiders and tropical tarantulas
● Project: Determine how habitat destruction, alteration, pesticide toxicity, and fragmentation affect tarantulas and their relatives.
● Why?: Since these spiders are long-lived (up to 20 years as opposed to 1-2 years for most spiders), extremely sedentary -i.e., they may live in the same burrow for years, and iteroparous (the technical term for reproducing multiple times during a lifetime as opposed to only once which is typical of most spiders) they are far more sensitive to environmental disturbances than other terrestrial invertebrates and thus potentially informative bio-indicators of an unhealthy environment – the proverbial “canary in the coal mine”.
Steve Reichling gathers data from tarantula burrows in Belize, including temperature, humidity, depth, the size and sex of the occupant, and microhabitat variables adjacent to the burrow.
The entrance to the burrow of a large redrump tarantula in Guatemala. That the burrow has an occupant is indicated by the veil of silk that the giant spider has spun across the opening, which helps maintain a stable temperature and humidity.
This redrump tarantula is being released back into its burrow after being implanted with a passive-integrated transponder – the same device that’s used to “chip” dogs and cats – enabling researchers to identify it throughout its 15-20 year lifespan.
Here, the underground portion of a purseweb spider’s silken tube is shown after being found in Overton Park’s Old Forest.
Three purseweb spiders are set up in a field experiment to examine how microhabitat variables affect their life history.
Many natural wonders in Overton Park’s Old Forest are easy to overlook. The ethereal beauty of a purseweb structure can be easily damaged by a carelessly placed foot. Please be careful and observant if you enter the Forest!
City Life: Forest Birds in the Greater Memphis Area
Bird surveys are taken at specific GPS points in the parks.
Barred owl observed through binoculars at a survey location.
Surveys are conducted in both winter and summer.
A pileated woodpecker forages in the winter near a survey point.
A Bird in the Hand: Monitoring Mid-South Bird Populations
Jeff Hill (Memphis Zoo Bamboo Crew Member, far right) and colleagues remove birds from nets just after sunrise.
Kristina Mitchell (Independent Biologist and Master Bird Bander, right) processes a bird prior to its release with Fields Falcone (Memphis Zoo Conservation Lab Manager).
A male orchard oriole just prior to release at the bird banding station.
Hibernation to Help Future Generations
A female Wyoming toad sits perched atop a rock at the Leadville National Fish Hatchery in Leadville, CO. Male and female toads can be easily distinguished by their throat coloration, with females having a light throat and males having a dark brown throat.
Wyoming toads raised at the Leadville National Fish Hatchery in Leadville, CO are weighed and measured prior to being put in their “hibernation boxes.” These toads will go 1-2 months without food during hibernation, so it’s important to monitor their weight and size so that we can get an idea of how physically healthy the toads are before and after hibernation.
Wyoming toads raised at the Leadville National Fish Hatchery in Leadville, CO are placed in plastic “hibernation boxes” to simulate a shortened winter in captivity. These boxes are outfitted with lots of holes for oxygen flow, moist moss, and carbon filter pads. To simulate cold weather, the boxes are placed in refrigerators set to 38o F. After a 1-2 month period, the toads are removed from the hibernation boxes and are ready to breed.
Wyoming toads are collected around the Laramie Basin in Laramie, WY to assess the reproductive health of the wild population. The toads like to live in the grass surrounding the pond and can easily be found hopping around in the summer months.
Kristin Hinkson injects a male Wyoming toad with hormones to stimulate sperm production in hopes of assessing the reproductive health of the wild population. It takes around 4 hours for the hormones to take effect in these toads, so we place them in plastic boxes with water and wait!
Guarding Against Inbreeding
An adult dusky gopher frog is held by researchers prior to collecting genetic material for later DNA analysis. Genetic material can be collected in many different ways: through cheek swabs, skin swabs, or tissue collection.
DNA can easily be extracted from dusky gopher frog eggs. Only one egg is needed per frog, and each female naturally lays hundreds of eggs.
Tubes filled with dusky gopher frog eggs are placed in an orderly manner as a first step of DNA extraction.
After DNA is extracted, the next step is to amplify a specific portion of the DNA that can give us clues about how much genetic variation is present. To do this, we use a process called polymerase chain reaction (PCR for short). This picture shows a 96-well plate where we can do 96 PCR reactions all at once!
DNA is amplified using this machine: a thermal cycler. This machine heats and cools the DNA to various sequences of temperatures—amplifying the DNA through a process called polymerase chain reaction.
Tracking Captive-Raised Frogs Released into the Wild
Investigating Impacts of Invasive Frogs
Animal: Cuban treefrog (Osteopilus septentrionalis)
Project: The Cuban treefrog was accidentally introduced to the Florida Keys in the 1920s and has been spreading north since then. Through a series of experiments in the field and lab, in collaboration with colleagues at the University of South Florida and University of Florida, this project investigates how Cuban treefrogs are affecting native frogs and how they are adapting to life in Florida.
Why?: As the Cuban treefrog continues to spread, it is negatively affecting native frogs by competing with them and preying on them. This project will help us understand how this invasive species is impacting native species and ecosystems, how it is adapting to its introduced range, and where range expansion may occur in the future.
Juvenile Fowler’s toad in the wild.
Juvenile Fowler’s toads in captivity.
Adult Fowler’s toad.
Reproductive Ecology of Snakes
Washing and drying bullsnake sheds to use for validation of hormone extraction methods.
Emily Lichtenberger, a Memphis Zoo research intern, grinding snake sheds and placing into tubes for hormone extraction.
Emily arranging ground tubes of sheds prior to adding solution for hormone extraction.
Are you pregnant?
Pregnancy was successfully detected for snow leopard cub born at the Memphis Zoo in 2013, 30 days in advance of birth. Early detection of pregnancy allowed staff time to optimize husbandry for pregnancy and set up den and birthing areas.
Communicating, Giant Panda Style