Groundhog

Marmota monax Order: Rodentia Family: Sciuridae

The name of the order “Rodentia” comes from the Latin word “rodere”, which means “to gnaw”. Groundhogs are part of the marmot group within Sciuridae, and are the largest members of the ground squirrel family.

Also known as a woodchuck

Overview

Groundhogs can be a wonderful addition to an ambassador group. As a native species, they can be used to further people’s understanding of their surrounding ecosystem, as well as garner appreciation for what many people consider to be a nuisance animal. Groundhogs are also a great example of an animal that has thrived due to changes to the native habitat (i.e. deforestation) made by humans, and so can help to drive home the lesson that actions can have unforeseen consequences. Groundhogs are generally quite food motivated and take well to training with positive reinforcement. They are low maintenance in terms of husbandry, as they are easy to litter train. They do not all take well to handling during programming, and those that do tolerate handling may not do so for all handlers. However, they can be trained for program use with a hands off approach, which can make them presentable by many different staff. They also do well in stage show settings. Their natural instinct to hibernate can cause seasonal challenges, as their slow metabolisms during the fall/winter months can cause them to be less apt to participate in food reinforcement work.

Natural History Information

Range and Habitat

Groundhogs are found throughout the eastern and mid-western United States, reaching as far south as the northern parts of the Gulf Coast states. They are also common throughout much of Canada, and even reach into the eastern-most parts of Alaska. Groundhogs will inhabit most any open land with wooded areas nearby. Deforestation has helped groundhogs to thrive by providing more of their preferred habitat.

Longevity

The median life expectancy for a groundhog in its native habitat is 2 years. In human care, the median life expectancy is 2-8 years.

Ecosystem Role

Though groundhogs are often seen as nuisance animals due to their burrowing habit, that habit can have positive effects on the ecosystem. Their burrows aerate the soil and provide space for excess rain water to run and store. Groundhogs are natural composters by bringing lots of vegetation down in their burrows as bedding, and that compost returns vital nutrients to the soil. Abandoned groundhog burrows are also important shelters for many other native species. Groundhogs themselves serve an important role in their ecosystem by being a common prey animal for a variety of predators.

Husbandry Information

Housing Requirements

  • Life Cycle Natural History Relevant Information
    • Groundhogs are true hibernators. If an ambassador groundhog is to be housed outside, appropriate accommodations must be made to ensure the safety of the animal during hibernation (i.e. supplemental heat, ample bedding, appropriate shelter). It would also be beneficial to be able to set up a camera to observe the groundhog in its shelter.
    • It must also be considered in an outdoor holding that a cement/fencing barrier must be present underground to prevent a digging-out escape issue.
    • Groundhogs are powerful chewers, and some wood/mesh barriers may be easily compromised.
    • Groundhogs are also adept climbers, so safety concerns may arise if the groundhog is able to climb the caging in its holding and reach heights where a jump down is from an unsafe distance, especially if no natural substrate is present in its holding, as a cement floor landing would be unforgiving. Installing acrylic on exposed caging can help to mitigate this risk.
  • Temperature, Humidity, Light Cycles
    • Groundhogs housed indoors seem to do fine with typical human-comfort range temperatures and humidity.
    • Lighting:
      • Akron Zoo: Normal work day light cycles seem fine as well.
  • Substrate:
    • Groundhogs housed indoors can do fine on cement floors, as long as the cement is not rough, which could irritate their feet.
    • Cypress mulch can work well as an area of substrate. Aspen works well as a litter box substrate. Straw, newspaper, and shredded paper are other favored substrates that can be gathered for bedding or used as waste cover-up.
    • A dig pit (can be as simple as a sandbox) with topsoil will also be appreciated by an inside groundhog.
    • It should be noted though, that the more substrate areas offered, the groundhog will be less likely to use just one area as its litter area, which could make servicing more time consuming. Regular substrate changes must also be considered if the groundhog uses multiple places to bury its waste.
  • Social Housing/Colony Management
    • Groundhogs are primarily solitary animals. Young groundhogs may continue to share a burrow with their siblings through their first summer, but usually disperse to dig their own hibernation shelters in early fall.
    • Groundhogs can demonstrate territorial behavior toward conspecifics. Adult groundhogs would most likely not live together without issue.
  • Other General Housing Requirements or Management information
    • Groundhogs are active animals and their holdings should offer them opportunities to perform natural behaviors. A dig area, climbing structure (Step 2/Little Tikes play structures work well and are easily cleaned), and various hide shelters will all be utilized by an ambassador groundhog.
    • Groundhogs are very neat about their bathroom habits and will readily use a litter box.
    • Some groundhogs can safely be provided with towels and blankets, as they love to wrap up in them while sleeping, but of course each individual should be assessed for chewing/ingestion of these materials.

Diet Requirements

  • Life Cycle Relevant Information
    • Diet in the Wild
    • Mainly herbivores, eating wild grasses, berries and crops. However, as adept climbers, they will climb trees to feast on leaves as well.
    • The occasional grub, snail or insect will also be consumed by a groundhog but are not considered to be omnivores.
    • Of course, groundhogs will also take advantage of home gardens and crop-growing areas. Groundhogs gorge all spring and summer in order to build up their fat reserves for the coming fall/winter hibernation.
  • Diet under human care
    • Groundhogs in human care do well on a diet of rodent block, various fruits, vegetables, and greens.
    • Some groundhogs also seem to like the different varieties of hay.
    • Browse such as sugar maple, mulberry, and sassafras are also favored items. The ambassador groundhog diet may be very different based on season as the groundhog’s metabolism slows way down and food consumption often greatly decreases in fall/winter.
    • Some groundhogs may also experience dry skin/dandruff episodes in spring as they lose their winter coat, and an EFA oil supplement on the diet can be helpful to relieve this.
    • Though groundhogs will likely work (train) for most items in their regular diet, some preferred treat items are dried fruits and nuts.

Veterinary Concerns

  • As a rodent, overgrowth of teeth could always be a concern, though it has never been an issue for the 3 Akron Zoo ambassador groundhogs.
  • Spay/Neuter of ambassador groundhogs
    • Many facilities with males report neutering males, though they are often used intact. When intact, they are prone to behavioral mood swings and can be territorial.
    • Females: anecdotes report females can used as ambassadors both intact and spayed with no real difference or issues, although be aware females can go into heat during a program, so this should be considered.
    • All Akron Zoo ambassador groundhogs have been spayed/neutered. A female on exhibit at Akron that was not spayed did become aggressive during her heat cycles.
  • Can be seasonally difficult to anesthetize due to slow metabolism/torpor.

Enrichment & Training

Enrichment

  • Behavioral Relevant Information
    • Groundhogs are diurnal and are natural diggers, chewers and climbers. Much of their active time is spent foraging for food.
    • They also spend a good deal of time gathering various materials for bedding.
    • Groundhogs have keen senses and are always on alert.
  • Environmental Enrichment
    • Groundhogs should be provided with opportunities to dig. A custom-made dig box or sandbox with topsoil and/or cypress mulch works well.
    • Groundhogs also should have various elevations for surveying. Good options are Step 2 and Little Tikes play structures with natural perching, and cinder blocks that can be arranged/stacked in different manners.
    • Groundhogs can also be harness trained so that they may explore outside (*Note – groundhogs can be skilled at backing out of even the best-fitting harness, so have a good recall in place!)
    • Groundhogs also utilize new materials provided for bedding gathering, such as newspaper, hay/straw, shredded paper, towels/blankets; oftentimes destroyed enrichment is then gathered as bedding
  • Behavioral Enrichment
    • Anything the groundhog can safely chew/destroy – cardboard boxes/tubes, packing paper, newspaper, non-waxed Dixie cups; there is an endless number of ways that diet items can be hidden/stuffed in these items to lengthen the feeding time of the groundhog; big cardboard boxes double as new hide houses, too
    • Materials for diet foraging – hay/straw, shredded paper, aspen; diet can be scattered in these materials to encourage foraging
    • Jolly/Boomer balls with peanut butter smeared on them
    • Produce chunks/nuts frozen in an ice block
    • Kiddie pool with water and diet items floating in dishes
    • Socialization/tactile time with trainers
    • Native bird calls auditory enrichment; raptor calls often elicit a stand/alert response
    • Olfactory enrichment in the form of spices/perfumes, or clean bedding from other animals (i.e. blanket from opossum’s bed)
  • Schedule
    • Akron Zoo: enrichment is required 3 times/week, but due to the high activity level of the animal, she generally receives some form of enrichment daily.
  • Other Enrichment Resources

Training

  • Behaviors Trained
  • Akron Zoo has had 3 groundhog ambassadors in the last 18 years. All were trained for kennel recall with a clicker, and all would willingly walk onto a baby scale on the floor.
    • The first groundhog did a simple A→B→A behavior on stage during shows, with B being meeting a trainer on stage.
    • The second groundhog did A→B→C, where B was pulling down a lever that turned on the lights on stage.
    • The current groundhog does A→B→A, where B is climbing a small set of stairs with a façade in front to make it look like the groundhog is emerging from its burrow.
    • All 3 groundhogs were also trained for tabletop behavior for classroom programming.
    • Tactile desensitization work (belly, back, feet) was also done.
  • Public Contact:
    • Akron Zoo: Groundhogs were accepting of tactile on the back from audience members.
  • Reinforcers used & schedule of reinforcement
    • Akron Zoo: Reinforcers are preferred items from the regular diet (rodent block, apple, banana, carrot, yam), and were used in both the shaping process, and in the maintenance of the established behaviors.
      • For show behaviors, since only a small reinforcement is given because behavior is designed to be quick, novel reinforcers (dried fruits/nuts) are used on a variable schedule alongside the delivery of regular diet items.
      • Some form of reinforcement is used throughout the duration of both tabletop and tactile behaviors.

Other

Colony or Breeding Management

  • This species is housed individually

Individual Identification

Programmatic Information

Messaging Themes

  • Groundhogs are a perfect example of a native species people see and/or have experiences with frequently.
  • Most people consider groundhogs to be nuisance animals, as they love to invade gardens and burrow under decks and storage sheds. However, most people are not aware of the benefits groundhogs bring to an ecosystem. Their burrows condition the soil through aeration and introduction of nutrients via composting. In addition, abandoned burrows provide shelter for many native species, including vital hibernation shelter for many reptiles.
  • They are also an important prey animal for a variety of native predators.

Threats and Conservation Status

  • Least concern; groundhogs have thrived with the changing landscape due to deforestation

Interesting Natural History Information

  • True hibernation is a fascinating biological process reserved for just a small group of mammals, of which groundhogs are one of the largest. During hibernation, the body temperature of a groundhog drops from 99oF to as low as 37oF, heartbeat decreases from 80 bpm to 5 bpm, and breaths go from 16 per minute to 1-2 per minute. Because the metabolic rate is so low, groundhogs may only lose 25% of their body weight during hibernation, despite not eating for upwards of 150 days.
  • Groundhogs do have brief periods of wakefulness during hibernation. It is thought these periods are necessary for waste elimination, stimulation of the immune system, and catching up on sleep, as the brain activity that occurs during sleep does not occur during hibernation. Males awake from hibernation first and begin visiting the females within their territory. This courtship routine helps females to be receptive of the male’s advances when the time is right, as mating must occur right when hibernation ends in order for the babies born to have enough time to grow and increase their fat reserves to survive their first hibernation.
  • Groundhog burrows are extensive. They can be 5-6 feet deep and may meander for well over 20 feet. There are multiple burrow entrances, some of them being plunge holes which enable the fastest escape from a quickly approaching predator. Burrows also have different “rooms” including a room for birthing/raising young, bathroom, bedroom, and hibernation den. On average, a single groundhog can excavate 400 pounds of dirt!

Did you know…

  • The very first Groundhog Day was celebrated on February 2, 1887.
  • Punxsutawney Phil has only a 40% success rate in terms of weather prognostication.

Handling & Presentation Tips

  • It is likely more rare than common to have an ambassador groundhog that enjoys or accepts being held.
    • Akron Zoo: Of the 3 ambassador groundhogs at Akron Zoo, one was totally fine with being held, even without constant food reinforcement, but the number of staff who could handle him in this manner was limited. One groundhog resisted being held, even when food reinforcement was offered. The current groundhog is accepting of being held, but food reinforcement is necessary or she gets wiggly.
  • Tabletop presentation is a good option for a hands-off approach to programming with a groundhog. However, a groundhog presented in this manner must be very desensitized to noise and commotion to be stoic on the table, rather than looking to escape (off the table!) if something alarms it.
    • Akron Zoo groundhogs presented on the table always have the option to retreat to their kennel, which is left on the table. Training a strong kennel recall behavior is beneficial to this type of presenting.

Use Guidelines

  • Ambassador groundhogs at Akron Zoo are really only limited in use by food motivation. This could mean that the groundhog is not motivated enough to exit the kennel and do a tabletop presentation in December, or that the groundhog may be much less motivated by the 3rd back-to-back classroom program.
  • Akron Zoo groundhogs are used for indoor programs only.

Pubic Contact and Interaction Guidelines

  • In a classroom setting with small groups (<25 people), groundhog can be touched with 2 fingers on the back while out on the table; participants can walk in single file past the table and touch one at a time. It is helpful to have the groundhog face toward the handler while handler provides food reinforcement, and to have handler initiate the touching.
  • For small specialized programs (i.e. Trainer for a Day), guests can participate in trained kennel and scale behaviors.
  • Groundhogs can also station on stage with a trainer in a show setting for tactile with special audience members (i.e. birthday party group)

Transportation Tips

  • Depending on the chewing habits of a particular groundhog, some modifications may need to be made to the travel carrier. Most current kennels have unguarded ventilation holes in the plastic in the back of the carrier, which are very easy for a groundhog to chew and enlarge. Some older model kennels do not have this ventilation and are more ideal for transporting a large, powerful rodent. If chewing on the ventilation holes is an issue, the area could be covered with a metal or acrylic plate. Chewing on the lip around the kennel door can also be an issue. The Facilities team at Akron Zoo fashioned a metal guard around the kennel opening lip.

Crating Techniques

  • Carrier is set up with several layers of newspaper and a sizeable towel/blanket. The newspaper is utilized by the groundhog as cover should any waste be produced while in the carrier. The groundhog uses the blanket to curl up in. The carrier itself (except the door side) is also covered with a fleece kennel cover for added comfort/security during travel. Akron Zoo groundhogs enter their kennels directly from the holding at the sound of a clicker.

Temperature Guidelines

  • Akron Zoo ambassador groundhogs go outside for enrichment purposes only. The minimum temperature is 45oF and upper limit is 75-80oF, with some flexibility based on availability of shade and animal behavior.

Acquisition Information

  • Akron Zoo: 2 of 3 ambassador groundhogs at Akron Zoo were acquired from local wildlife rehabilitation centers as non-releasable imprinted juveniles. We made arrangements for zoo staff to go to the rehab center to start socializing/training with the animal while acquisition paperwork was still being finalized, which was very beneficial. One groundhog was acquired from a breeder (Keystone Exotics – PA) in 2010. This animal was the most temperamental of the 3 individuals. I cannot say if this was just the personality of this individual animal, or if it reflects on the hand-raising/socialization provided by the breeder. Breeder had worked with other AZA institutions.
  • All Akron Zoo ambassador groundhogs have been spayed/neutered. A female on exhibit at Akron that was not spayed did become aggressive during her heat cycles.

Look for specialty/exotic rescues such as:

Resources

  • Rodent, Insectivore, Lagomorph TAG Chair – Rebecca Young, Assistant Curator, Ambassador Animals ryoung@zooatlanta.org

Contributors and Citations

  • Akron Zoo
  • Houston Zoo, Natural Encounters
  • Wild Wonders
  • Natural Science Center of Greensboro
  • Toledo Zoo

Comments from the Rating System

  • Natural Science Center of Greensboro: ours is bonded to certain individuals; easy care; can be harness-trained; dormant during the winter months.
  • Toledo Zoo: I would not consider this a good animal for holding while presenting.