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Feeding behavior in the cat – Recent advances
Abstract
The domestic cat, Felis catus, provides one of the few representatives of the order Carnivora whose behaviour may be studied within the laboratory environment. In recent studies of cat feeding behaviour, there has been a fundamental shift in emphasis away from internal factors of control, the homeostatic model, towards investigation of the controlling influence of external environmental factors on food choice and feeding patterns. Food choice is discussed in relation to prior dietary experience and the motivational level of the animal. Feeding patterns are shown to be strongly associated with food availability and energy economy rather than the momentary physiological state of the animal.
... Its changeable activity rhythm is in accordance with the adaptability this predator must show regarding the variety of rhythms of its prey ( Konecny, 1987 ): rodents are usually nocturnal while most song birds are diurnal. For most authors, the feeding pattern of the cat is entirely random, some pointing out the large variability between individuals ( Mugford, 1977 ;Mugford & Thorne, 1980 ;Kane et al., 1981 ;Thorne, 1982 ;Johnson et al., 1983 ;Randall et al., 1985 ). In fact, Thorne (1982) suggested that the cat has a behavioral repertoire containing different patterns of feeding, each being used when appropriate. ...
... For most authors, the feeding pattern of the cat is entirely random, some pointing out the large variability between individuals ( Mugford, 1977 ;Mugford & Thorne, 1980 ;Kane et al., 1981 ;Thorne, 1982 ;Johnson et al., 1983 ;Randall et al., 1985 ). In fact, Thorne (1982) suggested that the cat has a behavioral repertoire containing different patterns of feeding, each being used when appropriate. The cat could therefore adapt its feeding behavior according to the fluctuating seasonal conditions. ...
... Amplitude IS IV In contradiction with previous statements about behavioral arrhythmicity in the cat ( Hawking et al., 1971 ;Kavanau, 1971 ) or random patterns of eating ( Mugford & Thorne, 1980 ;Kane et al., 1981 ;Thorne, 1982 ;Johnson et al., 1983 ;Randall et al., 1985 ), the Figure 12. Mean food intake (g) of the cats (N = 6) every 20 min between 15:00 and 17:00. ...
Different synchronizers can modify daily rhythms during an annual cycle. Nevertheless, the fluctuation of these external factors is often ignored in studies on cat locomotor activity and feeding rhythms, thereby focusing on one single season. To fill this gap, the activity and feeding rhythms of six cats living in a research cattery, receiving natural daylight, were monitored during 3 weeks for each season. Although under minimal influence of seasonal fluctuations in ambient temperature and humidity, the cats showed maxima in daily covered distance during spring and autumn, and minima during winter. The activity and feeding rhythms followed 24-hour periodicity during all seasons and bimodality was detected, with decreased covered distance and food intake around midnight and midday. These daily rhythm troughs were robust and stable across seasons, whereas the inter-seasonal differences in activity level resided in the timing of daily peaks. However, the daily eating pattern was less affected by seasonal variations. Human interactions systematically enhanced locomotor activity and food consumption at the same time for each season, whereas spontaneous peaks of feeding and activity rose during the twilight times according to the season, confirming the crepuscular nature of the species. Human presence and attention seem responsible for more diurnal patterns in the studied cats. This study demonstrates that natural seasonal daylight fluctuations modulate the locomotor and feeding rhythms of indoor cats.
... In the wild, carnivores, unlike omnivores, display more neophilic than neophobic behavior (Thorne, 1982). Neophobia is more common when meals are served in unusual conditions (Thorne 1982) or if the animal is under stress (Bradshaw & Thorne, 1992). ...
... In the wild, carnivores, unlike omnivores, display more neophilic than neophobic behavior (Thorne, 1982). Neophobia is more common when meals are served in unusual conditions (Thorne 1982) or if the animal is under stress (Bradshaw & Thorne, 1992). ...
All pet food manufacturers claim their diets deliver exceptional palatability, but many companies
offer limited support for that claim. Palatability is complex. Expertise, innovation and leadership in
pet food palatability require an in-depth understanding of pet physiology and behavior, expertise
in diet formulation and manufacturing, as well as the development of innovative tools and
research methodologies for measuring diet palatability.
For veterinary therapeutic diets, palatability is essential. Pets are expected to eat veterinary diets exclusively
and compliance is directly linked to palatability. Illness may reduce a pet’s appetite, while the
therapeutic diet’s nutritional profile may make it inherently less palatable. Achieving exceptional palatability
in diets which are restricted in protein, fat or sodium, or which contain protein hydrolysates
(low molecular weight peptides which typically taste bitter), can be a significant challenge.
Royal Canin has always been at the forefront of palatability research. Years of study have led to an advanced
understanding of the three essential components of palatability: the pet (species and individual), the
environment (owner, home, lifestyle) and the food (smell, shape, texture, taste, nutritional composition).
... Különböző körülmények között egy ismeretlen, új íz esetében az elutasítás, vagy az előnyben részesítés egyaránt előfordulhat (Bradshaw, 1991). Néhány hétig tartó egyoldalú takarmányozást követően az új táp előnyben részesítését figyelték meg fiatal (Mugford, 1977, Ferrell, 1984 és felnőtt macskák (Hegsted és mtsai, 1956, Thorne, 1982 esetében is. Az anya vemhesség és szoptatás alatti táplálása szintén hatással van az utódok tápválasztására, valamint kiemelt hatása van a kölyökkor első hónapjaiban szerzett tapasztalatoknak, és az ekkor etetett tápoknak (Becques és mtsai, 2010, Hart, 1974, Stasiak, 2001és 2002. ...
... hiúz, vadmacska) tápláléka alapvetően kisemlősökből áll, ennek megfelelően a házimacska táplálóanyag igényének kielégítéséhez naponta többször, kis adag táplálékot fogyaszt el. Kísérletes módszerrel kimutatták, hogy a macskában van egy olyan mechanizmus, amely lehetővé teszi az energiabevitel szabályozását (Castonguay, 1981, Kane és mtsai, 1981, Thorne, 1982 és ezáltal az optimális testsúly megtartását. ...
... behaviour is unique in regard to circadian rhythm, cats being intermittent feeders. They have several short feeding periods, referred thereafter as meals, throughout the 24-h period and there is no direct relationship between the size of a meal and its timing (Mugford, 1977;Thorne, 1982). Cats may have 11 to 16 meals per day with 5 to 7 g eaten per meal (Kane et al., 1981(Kane et al., , 1987. ...
... Kane et al. (1981) have demonstrated that cats offered commercial cat food with different caloric content, quickly adjusted the amount of food ingested to maintain stable their calorie intake. Thorne (1982) also used commercial cat food with different water contents and found evidence for an energy intake regulation. In our study cats ate more VPK than LPK during a session and the difference of consumption clearly over-compensated the difference in caloric value of the VPK diet (average calorie intake/session: VPK = 258.3 ...
... The novelty effect is particularly persistent in puppies that have been fed on a single food for several weeks, but this type of dietary regimen has a similar effect on kittens (Mugford, 1977;Ferrell, 1984), adult cats (Hegsted et af. 1956;Thorne, 1982) and adult dogs (Griffin et af. 1984). ...
... 1987). Using commercial cat foods with different water contents, ' Thorne (1982) found good evidence for energy regulation. Overall. the published evidence suggests that cats can only regulate their energy intake over quite a narrow range (Fig. l), except that they can allow for changes in water content quite accurately. ...
... The apparent stability of the food consumption has been observed for the premium type, and the instinct of looking for new food was either not activated, or weak due to apparently low risk of malnutrition (Thorne 1982). ...
Impact of food type on long term consumption kinetics in group-housed domestic cats (Felis catus). The aim of the current research was to assess the impact of the type of dry food on the long term acceptance in cats, expressed as consumption curves. A group of 14 adult neutered domestic cats were subsequently offered three types of products: economy, medium and premium. The consumption of food has been carefully monitored each day of the experiment, which enabled the drawing of the precise consumption curve. The average daily consumption showed differences between feeding periods (98.33, 61.17 and 55.04% for premium, medium and economy diet type, respectively). In all groups the monotony effect has been observed, but the relative stability of the consumption has been observed only in cats fed with the premium type of food. The attractiveness of the economy type of food was distinctively low, resulting in a regularly waved consumption curve. It can be concluded, that the prolonged offering of a particular type of complete dry pet food within the limits of metabolizable energy requirements may potentially lead to adverse consequences for cats. The food consumption level that supplies the minimal daily energy amount can likely result in imbalanced macronutrient intake.
... In addition, the cats were exposed to the diets for 16 h each day and the study period was longer (42 days) allowing for a more complete anatomical adaptation to the intake of higher volumes of food. Our findings are also consistent with those of Thorne (1982) and Castonguay (1981), who Fig. 1 Pattern of food intake of experimental diets for cats with different insoluble fiber sources. Mean intake of each 2-h interval recorded. ...
Fibre is generally considered to dilute food energy, alter intestinal transit time and promote satiety; however, in cats, conflicting results have been found. In this study, two insoluble fibres were evaluated in four feline diets: control (no added fibre); diet with 10% sugar cane fibre; diet with 20% sugar cane fibre; and diet with 10% cellulose. The experiment was conducted with 32 cats, eight animals per diet, over 42 days: 1-7 for diet adaptation; 8-14 for total collection of faeces for digestibility; 15-17 for fresh faeces collection for fermentation products measurements; 18-20 for gastrointestinal transit time determination; 21 and 37 to evaluate the pattern of food intake; and 22 and 42 to assess satiety. Means were compared by analysis of variance and orthogonal contrasts, and the pattern of food intake was compared by repeated-measures analysis of variance (p < 0.05). The cats exhibited increased food intake after fibre addition to the diets (p < 0.05), achieving similar energy consumption. Cellulose and the two levels of sugar cane fibre reduced nutrient availability and energy digestibility, but only sugar cane fibre reduced fat digestibility (p < 0.05). Faecal output and the number of defecations per day increased with fibre inclusion (p < 0.05). Gastrointestinal transit time did not change with sugar cane fibre inclusion, but it was reduced with cellulose addition (p = 0.032). The pattern of food intake did not change, but cats fed fibre-supplemented diets exhibited greater consumption of a challenge meal, increasing energy intake (p < 0.01) when exposed to a palatable, energy-dense food.
... A preference in domestic cats for several small meals each day (Bradshaw, 2006) probably reflects multiple daily kills by feral cats when food is continuously available. When food is limited cats will as readily gorge on infrequent large meals (Thorne, 1982). Prey size influences the impacts of feral cat predation; on the Australian mainland this impact falls most heavily on species weighing less than c. 200 g (Dickman, 1996). ...
The need for lethal control of feral cats will remain in some contexts and potentially increase in others, alongside an obligation to develop and apply methods that are as cost-effective, humane and target-specific as possible. Drawing on practices particularly used in Australia, New Zealand and on offshore islands we review current lethal techniques applied for feral cat removal, such as shooting, trapping and poison baiting, and how our understanding of feral cat behaviour has influenced their development and application.
... A preference in domestic cats for several small meals each day (Bradshaw, 2006) probably reflects multiple daily kills by feral cats when food is continuously available. When food is limited cats will as readily gorge on infrequent large meals (Thorne, 1982). Prey size influences the impacts of feral cat predation; on the Australian mainland this impact falls most heavily on species weighing less than c. 200 g (Dickman, 1996). ...
... A preference in domestic cats for several small meals each day (Bradshaw, 2006) probably reflects multiple daily kills by feral cats when food is continuously available. When food is limited cats will as readily gorge on infrequent large meals (Thorne, 1982). Prey size influences the impacts of feral cat predation; on the Australian mainland this impact falls most heavily on species weighing less than c. 200 g (Dickman, 1996). ...
The need for lethal control of feral cats will remain in some contexts and potentially increase in others, alongside an obligation to develop and apply methods that are as cost-effective, humane and target-specific as possible. Drawing on practices particularly used in Australia, New Zealand and on offshore islands we review current lethal techniques applied for feral cat removal, such as shooting, trapping and poison baiting, and how our understanding of feral cat behaviour has influenced their development and application.
... It has been shown that carnivorous animals, such as cats (Felis catus), prefer rare diets to familiar ones (Thorne, 1982), which may serve as a means of optimising their diet, although there is little evidence to suggest that cats modify their feeding behaviour based upon the nutritional content of the meal taken (Bradshaw et al., 1996). Being opportunistic carnivores, mink may be equally less likely to respond with inhibition of feeding behaviour towards novel food, and introducing food as stimuli in testing novelty responses may not apply to mink, although useful in other farm animal species (e.g. ...
The study aimed to (i) describe the response of farmed mink towards familiar and novel food, and (ii) assess the suitability of using novel food in order to measure fear responses in mink. A total of 48 farm mink from two behaviourally selected genetic lines were caged individually with one standardised daily feeding. The experimental feedings were carried out in a balanced order on 2 successive days. Behaviour of the mink was video recorded for 10min after food provision. In general, the mink were reluctant to approach and eat the novel food compared to familiar food, which indicates a neophobic feeding strategy, i.e. increased latency to come close to (P<0.01) and eat (P<0.001) the novel food, and a higher frequency (P<0.001) and a longer duration (P<0.001) of sniffing. Provision of unknown food items may be used to evaluate fear responses in mink since mink respond reluctantly towards novel food. However, high inter-individual variation in the present study obliterated a previously shown difference between confident and fearful mink, suggesting that this method for measuring fear responses in mink is appropriate only on a large animal material.
... This strategy should reduce the probability that an unbalanced diet is taken because no 2 foods with markedly different flavors should contain the same nutritional deficiencies, even if these cannot be directly detected by cats. Powerful monotony effects were detected in both kittens and adult cats, and in both catteries (6,37) and free-ranging populations (38). The strength of this effect on preference appears to be greater in free-ranging cats, such as those on farms or taken in as strays, than in cats raised exclusively on nutritionally complete diets (39). ...
The dentition, sense of taste and meal patterning of domestic dogs and cats can be interpreted in terms of their descent from members of the order Carnivora. The dog is typical of its genus, Canis, in its relatively unspecialized dentition, and a taste system that is rather insensitive to salt. The preference of many dogs for large infrequent meals reflects the competitive feeding behavior of its pack-hunting ancestor, the wolf Canis lupus. However, its long history of domestication, possibly 100,000 years, has resulted in great intraspecific diversity of conformation and behavior, including feeding. Morphologically and physiologically domestic cats are highly specialized carnivores, as indicated by their dentition, nutritional requirements, and sense of taste, which is insensitive to both salt and sugars. Their preference for several small meals each day reflects a daily pattern of multiple kills of small prey items in their ancestor, the solitary territorial predator Felis silvestris. Although in the wild much of their food selection behavior must focus on what to hunt, rather than what to eat, cats do modify their food preferences based on experience. For example, the "monotony effect" reduces the perceived palatability of foods that have recently formed a large proportion of the diet, in favor of foods with contrasting sensory characteristics, thereby tending to compensate for any incipient nutritional deficiencies. Food preferences in kittens during weaning are strongly influenced by those of their mother, but can change considerably during at least the first year of life.
The plastic nature of cat behaviour allows this “friendly symbiont” of humans to adapt to various housing conditions. Beyond daylight, one could wonder if other environmental factors affect its patterns. Yet, how its activity and feeding rhythms are impacted by its environment is rarely studied in standardised conditions between populations. We compared the behaviour of cats living in a 29 m2 indoor room and cats living in a 1145 m2 outdoor enclosure, tracking them simultaneously in summer for 21 days, with advanced technologies. Both populations received daylight but weather fluctuations only occurred outdoors. Bimodality was detected in the activity and feeding rhythms of both groups, while twilight triggered crepuscular peaks. Daily, the outdoor population covered more distance (4.29 ± 0.27 km; p < 0.001) and consumed more food (67.44 ± 2.65 g; p < 0.05) than the indoor population (2.33 ± 0.17 km, 57.75 ± 2.85 g, respectively), but displayed less rhythmic behaviours, assumedly because of rhythm disruptors met only in outdoor conditions. Finally, outdoor housing seemed to promote the exploratory behaviour of the cats at night, while indoor housing increased both meal frequency (p = 0.063) and the impact of human interactions on the feeding rhythms of the cats.
Cat ( Felis silvestris catus ) shelter practices may have important implications for cats' health and well-being. This study explored the relationship between husbandry practices and cat health in Hong Kong's shelters which are unregulated. Cat health was measured via body condition score (BCS), coat condition and signs of oculo-nasal discharge. A total of 314 cats in 24 cat shelters were assessed. A satisfactory BCS was associated with regular veterinary input, more than once per day disinfection and more than once per day change of water. The presence of oculo-nasal discharge — as a marker for upper respiratory tract infection — was associated with a lack of regular veterinary input and less frequent change of water within the shelter. A lack of regular feeding was the only factor associated with a dull coat. In summary, this study showed that certain husbandry practices had important associations with different aspects of cats' health for cats housed in an unregulated shelter environment in Hong Kong. These findings provide evidence-based support for husbandry guidelines or regulations for cat shelters which could have a positive impact on shelter cats' health and welfare.
Biological rhythms are of importance for living organisms as they help to schedule most behavioural processes within the most suitable temporal window. Literature on daily rhythmicity is scarce and conflicting regarding domestic cats. To sharpen our knowledge on the subject, we used advanced telemetry technologies to record and characterise the daily rhythms of locomotor activity and feeding in cats according to the seasons and housing conditions. The cats were sensitive to photoperiod and to human presence. Along 24-hour periodicity, they displayed bimodality in their daily patterns, with mid-day and mid-night troughs of locomotor activity and food consumption. The two main activity/eating periods corresponded to dawn and dusk at each season, regardless of the twilight timings, confirming the crepuscular intrinsic nature of the species. The feeding rhythm of the cats was more variable daily than their locomotor activity rhythm, recalling the opportunistic character of this predator. Cats displayed plasticity in their behaviour, such as weaker daily rhythms and more nocturnal exploratory behaviour outdoors, compared to indoors where they were more prone to routine. Our results open new avenues for developing nutritional and housing guidelines fitted to the rhythms of the cats according to their way of life.
Pet food palatability depends on first and foremost on the pet and is related to the pet food sensory properties such as aroma, texture, and flavor. Sensory analysis of pet foods may be conducted by humans via descriptive or hedonic analysis, pets via acceptance or preference tests, and through a number of instrumental analysis methods. Sensory analysis of pet foods provides additional information on reasons behind palatable and unpalatable foods as pets lack linguistic capabilities. Furthermore, sensory analysis may be combined with other types of information such as personality and environment factors to increase understanding of acceptable pet foods. Most pet food flavor research is proprietary and, thus, there are a limited number of publications available. Funding opportunities for pet food studies would increase research and publications and this would help raise public awareness of pet food related issues. This mini-review addresses current pet food sensory analysis literature and discusses future challenges and possibilities.
The behaviour of a colony of eight laboratory cats and their reactions to a familiar and unfamiliar person were recorded and analysed. Seven of the cats were Domestic Shorthairs and one was a Persian. All were male and only one was intact.Maintenance behaviours (resting, sitting, drinking, eating, defaecating and urinating) were the most commonly observed behaviours (36% of observations). Comfort (grooming, scratching, sneezing, coughing, head shaking, stretching and yawning) and locomotory behaviours (walking, running, jumping from floor to shelf and shelf to floor) were also commonly observed (30% and 24.5%, respectively). Agonistic behaviours were rarely observed (1%). Other behaviours recorded included marking and investigatory (clawing, scratching post, rubbing cage, anal sniff, body sniff, wall/floor licking; 4%), play (2%) and vocalisation behaviours (2%).Walking, jumping, eating, drinking, scratching, rubbing, defaecating and urinating were observed most often between 08:00 h and 09:00 h. Running, walking, resting and sitting occurred most often on the shelves in the cage.The cats made more direct contacts with the unfamiliar person than with the familiar person. Significantly (P<0.01) more attention behaviours (rubs against person, claws person, stands and watches, jumps to floor, stretches head out to person, lies on floor near person) were observed on the first day of the human-cat study than on the second and third days for both the familiar and unfamiliar person.
The aim of this paper was to develop a protocol to study the anticipatory response in cats as a measure of welfare. Seven experimental cats were trained in a classical conditioning paradigm to associate a sound with food arrival, while sound and food were presented without contingency in four control cats. Increasing the interval between sound and food up to 60 s allowed a detailed description of cats' anticipatory response. Compared to control animals, experimental cats showed significantly shorter latencies to orient towards (average 2.96 s) and approach the source of the sound (12.98 s) as well as longer durations of exploring and standing by the source of the sound (namely 69.97 and 52.32%, respectively of the interval sound-food). Experimental cats also exhibited behaviours that may derive from predation patterns, eg short pauses and predatory crouch while approaching the source of the sound (namely in 28.93 and 29.64% of trials), rapid head movements while watching it (55.36% of trials) and pouncing on the food (9.29% of trials). This protocol should be further studied to assess its effectiveness in highlighting differences according to the welfare of individual cats.
Preferences for common food types (‘apostatic selection’) have been demonstrated in a wide variety of vertebrate predators, yet there are few examples of preferences for rare food types (‘anti-apostatic selection’). Anti-apostatic selection is predicted to occur when, among other things, there are nutritional benefits to be gained from the consumption of a mixed diet. We tested this hypothesis by examining the frequency-dependent food preferences of domestic cats (Felis silvestris catus) with different nutritional histories. Subjects were classified as being either nutritionally ‘experienced’ (farm and rescue shelter cats, with a history of scavenging for nutritionally variable foods) or nutritionally ‘inexperienced’ (cats reared indoors on high-quality, nutritionally complete diets). We tested for frequency dependence by allowing individuals and groups of cats from the two groups to select from high-density mixtures of two types of artificial food pellet. In experiments on individual cats, nutritionally experienced subjects showed significant anti-apostatic selection, whereas inexperienced cats produced only a weak anti-apostatic trend. In experiments on groups of cats, both inexperienced and experienced groups showed significant anti-apostatic selection. The apparent inconsistency between individual and group results could be explained in terms of the additional anti-apostatic effects that result from variation among individuals in group foraging situations (i.e. when the effects of individuals are pooled). Because other behavioural explanations, such as perceptual contrast and sampling effects, were unlikely to have influenced our results, we conclude that the differences in selection between experienced and inexperienced individuals were probably due to the differing extent to which the consumption of a mixed diet was beneficial. These experiments may offer some insight into the success of the domestic cat in urban areas: although obligate carnivores, they appear to possess flexible feeding strategies which will tend to allow them to select a reasonably balanced diet from nutritionally variable resources in, for example, refuse bins.
Reports 3 experiments with (a) 10 female hooded rats and their litters (reduced to 6 pups/litter); (b) 1 male and 4 female wild rats (Rattus norvegicus) and 2 litters (6 pups/litter) born to colony members; and (c) 6 litters of wild and 4 litters of hooded rat pups. Results indicate that adult Ss were capable of influencing their pups' choice of diet during weaning in 2 ways: (a) cues transmitted from a mother to her pups during the nursing period were sufficient to determine the dietary preference of the young at weaning, and (b) the presence of adult Ss at a feeding site was sufficient to determine the choice of feeding site by the pups independent of cues transmitted during the nursing period.
Studied feeding preferences of weaning rat pups in 4 experiments with 20 recently parturate female hooded rats and their litters (reduced to 8 or 12 pups per litter). Results show that cues associated with the diet eaten by a lactating female rat are transmitted to her young, probably via her milk, and are sufficient to markedly influence the food preferences of her young during weaning. For their 1st meals of solid food, the weanlings actively seek and preferentially ingest the diet their mother has been eating during the nursing period, even if that diet is relatively unpalatable. (15 ref.)
Research has borne out the concept of imprinting as a type of learning different from association learning.
Presents a supplemental version of a 1967 treatise on conceptual issues in the study of animal behavior. The need to establish multidisciplinary centers for developmental studies on the behavioral, physiological, and anatomical aspects of behavior is emphasized. (8 p ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
The hypothesis that constraints on the parameters of free feeding are the source of motivation in feeding behavior was explored in Guinea pigs. The effect of effort (FR size) on meal frequency, meal size and rate of eating was investigated when reinforcement consisted of an entire meal or a small portion of a meal. Frequency of feeding decreased and the duration and rate of eating increased when an entire meal was available. Frequency of meals was unaffected and rate of lever pressing and duration of meals increased when reinforcement consisted of a single food pellet. These data were taken to argue that there is a common pattern of changes in feeding behavior across species with respect to these variables and the value of these variables can be taken to describe the properties of different ecological niches.
Patterns of food intake were examined in cats both under ad lib feeding conditions, and when the availability of food was constrained by requiring the completion of fixed ratio schedules of bar presses to obtain a meal. As the ratio requirement was increased, frequency of feeding decreased, while both meal size and meal duration increased. Body weight did not decrease until the highest ratio requirements. When the caloric density of the diet was decreased, cats maintained bulk rather than caloric intake under all conditions of availability. It was concluded that environmental variables, particularly the availability and nutritional properties of the diet, are major determinants of natural patterns of feeding.
The intake of a freely feeding animal can be characterized by four parameters: frequency of meals, duration of meals, rate or intensity of eating, and choice of items eaten. The values of these parameters characterize species and the ecological niche they occupy. Constraints on any one of these parameters leads to compensatory changes in other parameters over the feeding cycle. Any change in performance of the instrumental behavior ancillary to feeding which causes the values of these parameters to recover their optimum or privileged value, defined by their niche, will be strengthened. These changes in performance reflect what is usually meant by motivation and the process of reinforcement.
As the cost of procuring access to food increases, caged laboratory animals have been found to reduce meal frequency and compensatorily increase meal size. Meal frequency and size, however, have been shown to be influenced by the availability of alternative activities. The present experiment tested the generality of the earlier findings to uncaged animals. The relationships obtained between meal procurement cost and meal frequency and size with a freely roaming cat were the same as those obtained with caged animals. Meal size and meal duration were highly correlated but no significant correlations were found between meal size and pre- or post-meal interval. The results of this research further support the ecological validity of a cost/benefit analysis of feeding behavior.
Rats were preexposed either once or seven times for either 20 or 120 min to a 1.0% saccharin solution. Retention of this flavor familiarization was then observed either 2 or 96 days following preexposure. Test day intake was directly related to both number and duration of preexposures but was not influenced by the retention interval. The results indicate that even a relatively brief familiarization experience is retained over prolonged intervals.
Conducted 3 experiments using 40 male Sprague-Dawley albino and hooded rats as Ss. No strict correlations between meals and intermeal intervals were observed in free-feeding patterns. Pooling of raw data into deciles did increase correlations, but also reduced data variance systematically. Reanalysis of raw data in relative terms (i.e., ratios of meals and intermeal intervals) yielded reliable meal pattern correlations, and indicated that feeding patterns are controlled by endogenous circadian signals of body nutrient depletion-repletion rather than short-term consequences of recently ingested food. Chronic treatment with insulin (which prevents mobilization of stored nutrients) appeared to attenuate the repletion signal, and termination of treatment (which leads to increased breakdown of stored nutrients) to accentuate the signal. Accordingly, the pattern of feeding may reflect lipid and/or glycogen metabolism. (19 ref.)
In 2 experiments with male hooded rats (N = 36) prior drinking of a distinctively flavored fluid lowered the subsequent palatability of that flavor. In a 2-bottle choice situation, preference shifted away from the flavor previously tasted; in a single bottle test, S drank more if 2 equally palatable flavors were alternated than if only one was presented. The effect was relatively short lasting, with recovery occurring within 30 min. It is suggested that this mechanism is an important component in the ability of the rat to self-select an adequate diet from a number of choices, since it would allow for the alternation among nutrients of different palatabilities in the absence of specific deprivations. (25 ref)