Curiousity in Zoo Animals

Curiousity in Zoo Animals- Glickman & Srogues, 1964

• Introduction: observed the responses by zoo animals when exposed to novel objects placed within the enclosure, and they used a diverse set of stimuli that varied in colour, shape, texture and odour. A cool little experiment by Brehm and Darwin (1874) where they placed a toy snake as well as a live snake in a box within a monkey cage and observed a very human like curiousity. the monkeys over time would lift the box lid to peek inside at the snake on multiple occasions.
• they make a good point, they note the fact that different stimuli may be perceived differently based on the species, however the only way to do this is by observing differences by presenting the stimuli in the first place. Tinbergen (1951) makes note of the initial part of this as well – basically the idea of using stimuli fitted to a subject’s natural behavioural repertoire is quite old but hard to put into practice because of comparison between species. How do you compare the apples to oranges (never understood that cause they were both fruit -_-)
• Subjects: 187 mammals, 20 reptiles, additional 35 primates – check the paper for specific species (over a 100 species observed)
• Procedure: Each animal was tested individually either in home cage or familiar cage, carried out between 5pm and 11pm, when zoo was closed, and tried to test during animals active cycle, made sure they were alert at the start. Mammals were fed from 1-4pm, reptiles fed once a week, mammals were satiated prior to testing while some reptiles may have been hungry. Stimuli: wooden blocks, 2 lengths of steel chain, pieces of wooden dowel, lengths of rubber tubing, crumpled piece of paper. This was also the order of presentation. Used new pieces of stimuli for every animal except the chains which were carefully washed to reduce odour contamination. Smart idea to scale the objects based on animal size, they had large medium and small objects. Also the objects were chosen because of easy replacement and the difference in texture, odour and other characteristics. I personally think as much as the objects may be really different, in the sense of encouraging or inciting curiousity they may all be the same, except for maybe the primates that could manipulate pretty much all of these stimuli.
• Exposure Procedure: each stimuli was presented for a single 6min test session with an interval of 5-20min between test sessions. 72 5-second periods were used to score the subjects behaviour in relation to the stimuli in which eye direction and contact was noted. Also accidental contact wasn’t noted, this occurred when the animal touched the object while moving around the enclosure, determined by lack of eye orientation. Also noted how they interacted with the objects (sniffed, chewed)
• Results: primates showed significantly more orienting glances than mammalian carnivores who show more than rodents. Found that the responses from rodents, primitive mammals and reptiles were so few that they could not be compared meaningfully. Checked gender effects and found no significant differences, similar case when observing for age variation.
• Results: They outline how different primate groups responded differently compared to each other, like how lemurs seemed to prefer olfactory investigation while baboons and macaques preferred heavy manipulations. The carnivores were the most consistent with most of them being highly reactive to stimuli. For Reptiles the most reactive animal was the orinoco crocodile which did show signs of habituation comparable to mammals, They also further emphasize that the king cobra which is known as the most intelligent reptile by a study in 1933, had shown very little interest in the stimuli.
• Discussion: Curiousity may have evolved as a way to to increase survival in an everchanging environment, a way to collect pertinent novel information, thus animals that live in environments that require moderate investigation to find food would also benefit from a sustained level of curiousity. Also investigation occurs at the risk of predation, especially predator awareness, thus reasonable to believe that animals that with defensive mechanisms or strategies to make up (lots of cover in the environment) for this would be able to allocate more energy towards investigation.
• 1. Primates: This may explain the high level of curiousity witnessed in the mentioned groups, as well as the differences between species of the same group, for example tree top living primates had a heightened need for visual exploration to differentiate fruit amongst trees and branches, while baboons were more terrestrial and had to manipulate abiotic factors around them to get food like flipping rocks and checking crevices.
• 2. Carnivores: these animals are constantly in competition both with surrounding conspecifics but also with the prey they hunt, also as juveniles play behaviour that later matures into hunting techniques and take downs may also be a reason for the high reactivity to the stimuli. Furthermore they have to meet the demands of the environment which usually involves long periods of sustained investigation.
• 3. Rodents: The species that had defensive armor like the porcupine were far more reactive than the shy small mice, which has no defensive features other than teeth and claws. But only had small amount of data so take with a grain of salt.
• Discussion: Makes note that brain development may not be purely indicative of curiousity since some of the primitive animals did show high levels of reactiveness.
• Discussion (Captivity effects): Start off, they make some real good points!! Captivity for one takes away the need for investigation of food as well as predator avoidance, some key things which may encourage investigation or highly reactive behaviour. Also captive animals are constantly exposed to novel stimuli entering their enclosures by zoo keepers thus build a perception that most objects entering are either innocuous or positive. Furthermore captive animals are most likely bored, which temporarily may encourage investigation but long term probably has the opposite effect and may lead to bizarre stereotyped behaviour. These stereotyped behaviours block attention to environmental stimulation and thus reduce the magnitude of the subjects response to the stimuli. GOOD THING TO CHECK IS WILD AND CAPTIVE BRED WHEN DESIGNING A STUDY, i guess most would be captive nowadays anyway but just in case.

• Great study, the attention to detail is really good and I can see why they decided to go with the very simple and easy to replace items. Without them covering the basics we couldn’t ask the questions we ask today. I love their reasoning for a lot of the concepts!
• Dissection: okay to begin my biggest pet peeve is the stimuli used, I think we should try to use stimuli that is species-specific or at least stimuli that are running hot on all ends: that means odour, touch, taste, visual, hearing. This is because we are asking these animals to investigate objects but if these objects don’t pander to the expertise of the animal we won’t be able to gauge their true capabilities. This is probably what led to a lot of the slightly incorrect conclusions drawn at the end, because based on the evidence the reptiles did not perform, hence probably not curious while in reality why be curious about something that is just as monotonous as your surrounding stimuli even if it is novel, if anything it highlights the fact that novelty on its own is not enough of a catalyst. However the biggest question is how do you run a comparative cognitive study across multiple species that perceive the world in a multitude of ways, unless you run a battery…… i mean in the strictest sense you could potentially devise an experiment that does expose multiple stimuli in succession that all pander to one of the aforementioned senses and then expose all species to said succession. Atleast then you can compare everything, but given sample size and large scale of a zoo it would be difficult but definitely doable.