Background

Over 200k rats are used for research purposes per year in the UK alone. Annex III of the EU Directive 2010/63 states a minimum size for housing cages for adult rats up to 600g of 800cm2 of floor space and 18cm in height. Some rats are housed in taller enclosures (26-30cm), which are strongly recommended to allow the rats to perform their full natural range of movements. As well as being limited in space, these cages do not allow rats to have a full sensory experience or perform motivated/natural behaviours.

What is it like to be a rat?

Rats primarily interact with their environment through scent (olfaction), touch (tactile) and sound (auditory). Pheromones released from scent glands and present in their urine and faeces are used to communicate information such as health, kinship, readiness to breed as well as states of anxiety or distress. Rats use their whiskers much like we use our hands, purposefully using them to detect nearby objects and surfaces. Rats also communicate through ultrasonic vocalisations with 22kHz sounds being associated with a state of alarm or distress, while 50kHz sounds reflect a positive emotional state. Their vision is relatively poor, however, they are highly sensitive to motion and will startle in response to rapid or sudden movements.

What is important to a rat?

Laboratory rats retain many of the behaviours of their wild ancestors and will readily present them if given the opportunity. The following behaviours are particularly important for rats:

• Rats are nocturnal animals and are especially active during the early evening and just before sunrise.
• Rats are social animals living in extended family groups.
• Wild rats excavate and inhabit an extensive network of tunnels and laboratory rats exhibit analogous burrowing behaviour.
• Rats engage in play behaviour (e.g. wrestling and chasing) from a young age and these activities are important for establishing social ties, which adult rats will reinforce by grooming.
• Rats perform nesting behaviours which allows them to regulate their microclimate in addition to raising young. 
• Rats look for areas to shelter and spend much of their time exploring their environment. 
• Rats require objects to gnaw on (e.g. soft wood blocks, hard pellets, cardboard tubes) to prevent their teeth overgrowing.

Production farming is a tricky ecosystem to manage, trying to balance productivity and efficiency with sustainability and welfare. Demands for poultry, both as meat and for eggs, continue to grow. Industry strives to meet these demands using strategies such as increasing the number of animals and/or genetic selection of birds that exhibit desirable traits. However, the costs resulting from these strategies are often paid through welfare reduction (e.g. insufficient space per individual caused by overcrowding, limited or no parental contact/care). Initiatives to improve chicken welfare such as “End the Cage Age” have been successful in putting into motion the banning the use of cages for egg-producing chickens across the EU and UK. Yet even welfare-focused movements such as this can amplify other welfare problems within the production farming system.

• Both broilers and layers are separated from their mother very early, so have no role model to learn appropriate behaviour. This can be detrimental to their welfare. They would usually shelter under the mother hen for warmth and comfort. Heat lamps are provided, but they provide light - whereas chicks normally have dark conditions some of the time (under mother hen). Dark brooders have been shown to be beneficial, but have not been widely adopted in farming practices.
• Amongst laying hens, preening between birds is a normal social behaviour, associated with bonding and role in hierarchy. Pecking is a natural precocial behaviour, based on an urge to find food, but it can be misdirected into compulsive feather pecking (termed “severe feather pecking” SFP or “injurious feather pecking”), when some individuals are targeted by another individual or a group of individuals. When the behaviour has started, there is often an outbreak. SFP not only affects welfare but also productivity (i.e. fewer eggs laid). There are several contributing causes of SFP, including nutritional deficiency, stress/frustration, crowding, lack of mother model.
• Several methods of preventing SFP exist but none of them are 100% successful or are welfare concerns themselves. It is also very difficult to predict when SFP outbreaks will occur. Visually, it is only detected when severe damage to birds is evident to the farmer. Research suggests that vocalisations (squawks) caused by victims of SFP could be a way to identify when pecking occurs, but it again is not fully accurate because birds can also squawk for other reasons. Thus, we currently have no ways of intervening SFP outbreaks because it is difficult to detect it early before it spreads.
• Similarly, an outbreak of squawking can ensue after one bird has cried out. Does each bird call indicate stress? Or is the bird just copying? Research has established a relationship between feather damage and vocal transmission.

Along with bonobos, chimpanzees are the closest extant relatives of humans in the animal kingdom.

They have complex cognition, showing evidence of Theory of Mind (the ability to infer that others have mental states similar to one’s own) and displaying sophisticated tool-usage in the wild, such as using stones as hammers and anvils to crack open nuts.

Chimpanzees are much stronger than humans, about 2-4 times as strong, and their strength helps climb trees to forage and nest, living an arboreal lifestyle.

Studies have shown remarkable memorization abilities, including on tasks where they outperform humans (https://youtu.be/qyJomdyjyvM). This has led to a “cognitive trade-off hypothesis”, which posits that common ancestors of humans and chimps had superior memorization abilities which the human lineage gave up when their brains acquired language skills and processing absent in other primates, while chimp brains kept the speedy memorization and recall abilities (i.e. their brains do not do semantic processing like humans, so they can devote more cognition to rapidly memorising and recalling stimuli).

Bees are smart learners and excellent at finding sources of nectar and pollen in their environment. However, several factors in the environment can affect their learning and welfare.

• Pesticides disrupt their olfactory learning and navigation abilities. There is evidence that bees might prefer nectar with pesticides, making it a harder task to prevent them affecting bees.
• Physical stress from predators leads to them being more cautious and less likely to approach ambiguous stimuli.
• Habitat loss has also been implicated in reduced bee survival by removing access to floral resources.
• Wild bees (bumblebees, solitary bees) have the additional issue of possible competition for resources with managed bees.

Several of these factors have therefore led to problems for managed bees as well as declining and poor health of wild bees. Things to know:

• Aversive to temperature above 44 deg C
• Aversive to movements and cautious - indicates predators - mammals (badgers), birds or invertebrates (camouflage spiders) 
• Aversive to electric shocks and sensitive to electric charge
• Aversive to quinine
• Pay attention to chemical cues - on flowers: “I was here so go to another source of nectar”, alarm pheromones from honey bees
• They seem to be social learners - is there a bee culture?
• They are smart
• Olfactory signals are volatile

We have 2 male Arctic foxes at Northumberland Zoo. They are brothers that share the enclosure full time so enrichment would serve them both. As with all canines, Arctic foxes have an excellent sense of smell which they will use to hunt and forage in the snow and other substrates. For their pounce behaviour they will also rely on their keen hearing to pinpoint the location of prey under the snow before they pounce.

They are one of our trickiest species to enrich. This is due to the fact that they ingest everything that they shouldn't and many arctic foxes have died in captivity due to ingesting foreign objects - so as you can imagine, we are extremely careful (and limited) with what we can give them.

Consequently, any enrichment cannot include fabrics, cardboard or paper as these are known to be ingested by the foxes. We look forward to hearing some ideas!

The enclosure

It is all outdoors with natural substrate, hills, dens and platforms. It is on a slope and there are no vast areas of open flat ground, which is one thing to bear in mind when looking at the footprint of the enrichment. There are also some small conifer trees in the enclosure however these are not mature enough yet to fix anything too. One final thing to know is there is a perimeter electric fence which acts as containment in this open top exhibit. Enrichment items must be kept clear of the electric fence so as not to affect it.