Enrichment Proposal I

Vulpes vulpes: Hunting

Vulpes vulpes, more commonly known as Red Foxes, are members of the Canidae family. They eat a variety of food, sometimes changing their diet from season to season. They are considered opportunistic feeders who will feed based on availability. Their diets usually include small rodents, rabbits, hare, insects, wild fruits and berries. Foxes are great at scavenging, hunting and caching. They carefully hide food for future use by burying it underground and disguising the spot with leaves and twigs. They will sometimes relocate their provisions.

Red Foxes are predators of small prey; these animals are high-strung and have quick reactions, which means that foxes have to stalk their prey quietly to be able to catch them. A fox’s hearing is very sensitive to lower noises, frequencies that correspond to rustling and gnawing sounds of small animals. They are capable of locating sounds within inches of their exact location.

Types of prey:

J. David Henry groups the types of animals Red Foxes eat, into 4 main groups:

• Insects: Crickets, grasshoppers, and beetles. Sometimes flies and moths.

• Lagomorphs: Includes rabbits and hares, who flee by running.

• Small Burrowing Animals: They flee down a burrow or dash under objects like rocks or fallen trees.

• Arboreal Prey: Birds and tree squirrels. These animals have high visual acuity, they flee upwards, and they keep a watch for predators from high perches.

The techniques that foxes use to hunts these types of prey is also different, each one unique to the circumstances.

Hunting Techniques:

• Insects: Hunting insects is something that foxes do more casually. Insects have weak escape behaviors, and they only provide the fox with a small amount of food. Usually, foxes are doing something else, and they hear an insect, and they simply walk over and bite down. When insects hop or fly away, they use their muzzle to poke around, or they do something called foot stamping. The foot stomping causes insects to move, and then the fox is able to locate them by the sound of rustling or movement.

• Lagomorphs: These hunts start out with stalking and end up in pursuit. Usually, hares and rabbits bolt and flee as soon as they detect the fox, who then follows them galloping behind. The fox tries to get close and bit down on the leg or rump, which causes the prey to start zigzagging to create more distance between them. This can go on for a while, and two things can happen; either the hare escapes into a briar patch too dense for the fox, or the fox is able to catch the leg, pulling the hare off of its feet and they both fall to the ground. The fox then quickly stands up, pins it to the ground and bites its neck or head.

• Small Burrowing Animals: A fox must approach these animals without making a sound. A cracking twig will cause the prey to stand completely still, making it hard for foxes to find them, or they will flee down a burrow. The hunt for these prey begins when a fox hears them and goes into mousing position. Mousing position is when a fox lifts its head and neck high and stares intently. They can try to locate the prey by scent, but more commonly, they tilt their heads trying to pinpoint their location by sound. If this doesn’t work, they’ll stalk their prey. They lower their head, crouch down slightly. To avoid making sounds, they place their forefoot down lightly and bring it back up to choose again, and then they place their back feet exactly where the front feet were. Once the prey was located, they go into mousing position to accurately pinpoint the location, they crouch deeply and lunges, arching through the air. At the end of the lunge, the fox tries to pin down its prey.

• Arboreal Prey: When hunting birds or tree squirrels, foxes rarely lunge. They more commonly stalk their prey and charge them in a crouched dashing run. This is not their most successful hunting technique, so they do not really search for this type of prey, they hunt them if they encounter them in a vulnerable position. As soon as they see one on the ground, the fox crouches so low, that their belly is touching the ground, and remains completely still with its ears alert. The stalking pace then turns into a trot, then into a gallop, and then finally they charge, trying to catch the prey with their bite instead of a stab like it does with small burrowing animals. When hunting these type of prey, foxes try to synchronize their movement with the prey’s movement to mask the sound, but the most crucial part of this hunting technique is minimizing visual cues.

Red fox: The Catlike Canine

Previous enrichment testing:

Feeding enrichment in an opportunistic carnivore: The red fox

Claudia Kistler, Daniel Hegglin, Hanno Würbel, Barbara König

They compared four different methods of feeding enrichment that were based on natural foraging strategies of opportunistic carnivores, red foxes. The feeding enrichments consisted of electronic feeders delivering food unpredictable in time which were successively combined with one of the three additional treatments: a self-service food box, manually scattering food (unpredictable in space), and an electronic dispenser delivering food unpredictably both in space and time.

All four feeding enrichments significantly enhanced individual behavioral diversity and activity compared to a conventional feeding treatment. The proportion of food-related behaviors, such as food searching or food acquiring, increased the most during the feeding treatment with the highest spatial and temporal unpredictability. There was also an increase in exploratory behaviors, such as locomotion and monitoring behavior. The findings show that any temporal and/or spatial unpredictability in the presentation of food has a stimulating effect on the foxes’ behavior.

Enrichment Proposal 1:

This first proposal is inspired by the way in which foxes hunt small burrowing animals. The main parts of this hunting technique are the pinpointing of the sound, the stalking, the lunge, and the possibility of the animal escaping down a burrow if a sound is made. To engage a fox in this type of behavior, I thought about creating a small motorized container with a speaker and a sound detector. This container will enter the fox’s habitat, play gnawing sounds pertaining to small animals to attract the fox. Ideally, the fox becomes engaged and start stalking it. The moment the fox makes a sound, the sound sensor will detect it, and turn on the motors to make it run away from the fox as a small animal would. For the fox to get to the container, he will have to be completely silent. The sound sensor would have to be configured to detect very low frequencies, so only something like the sound of a breaking twig would set the container running. In this type of hunting, foxes try to pin down their prey before biting, so ideally the fox would not bite down on the container, and it could be reused.

Enrichment Proposal 2:

This second proposal comes from the hunting of arboreal prey. Foxes are usually very unsuccessful with this type of prey, but it is an interesting one because they rely on hiding and the element of surprise. This type of hunting rellies more on visual cues than on sound signals. The fox has to see this type of prey on the ground, in a vulnerable position to try to hunt them, and he has to avoid being seen or else, the prey will flee. For this second proposal, I had in mind a hanging motorized food tray with some type of motion sensor, either ultrasonic or infrared and fishing wire. This would ideally hang from the top of the cage. The motor would unwind the wire, lowering the tray to the ground, trying to get the fox to engage with it visually and through smell. The fox would have to approach the tray very stealthily and quickly try to catch it. Otherwise, the motion detector would see it and immediately activate the motor that would send the tray back up, imitating a bird or squirrel fleeing up. This could be repeated several times until the fox is able to catch it, or it could be done once throughout the day, whether successful or not, just like it would happen in nature.

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