National Repository of Grey Literature 81 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
The occurrence and the function of eyespots in the vertebrate colouration
Helebrant, Václav ; Fuchs, Roman (advisor) ; Pipek, Pavel (referee)
Eyespots are a striking feature in the colouration of many animals. These are spots of a circular shape, which in their external appearance subjectively resemble the eyes of vertebrates. In invertebrates, they are found in insects, crustaceans and molluscs, while they are most widespread in butterflies. Within vertebrates, eyespots are most common in fish. Among amphibians, they are found in frogs, but their occurrence has not yet been mapped in detail. Eyespots occur rather rarely in reptiles and birds, and only remotely similar patterns can be found in mammals. Current research on the function of eyespots more or less reliably demonstrates that they play an important role in defense against predators or in communication within intraspecific interactions. The eyespots can fulfill the anti-predation function in two ways. According to the intimidation hypothesis, eyespots serve to prevent a predator from attacking. However, it is not yet entirely clear whether the spots frighten predators because of their similarity to the eyes of dangerous animals, or whether predators avoid the spots because of their conspicuousness and contrast with the surroundings. According to the deflection hypothesis, eyespots attract predators, but they direct the attack away from vital parts of the prey's body. In...
The effect of tactile and acoustic signals on reduction of signs of stress in dogs
Murínová, Karolína ; Santariová, Milena (advisor) ; Fuchs, Roman (referee)
Being touched by the human brings up physiological and behavioral feedback in the dog which indicates touch has a calming effect. Measurements taken include noticable changes in blood pressure, heart rate (HR) and heart rate variability (HRV) as well as hormonal changes - especially oxytoxin and cortisol levels. The primary objective of the fieldwork was analyzing the influence human touch has on the stressed dog and trying to bring its stress levels down using voice stimulation and a combination of voice and tactile stimuli. The dog was put into an empty room, causing elevated stress levels. After a fixed period of time the dog's owner would enter and try to calm the dog down using afromentioned treatments. The owner would then sit down on a chair and pay no more attention to the dog. The relaxing effect is being evaluated using two cardiovascular parameters, HR and HRV, and behavioural signaling. Measurements of each of the sessions are being taken three times when the dog is not moving. Phase 1 is when the dog is alone in a room, Phase 2 is taken just after the interaction with its owner has ended and Phase 3 at the end of the experiment when the dog's stress level is still. The results showed that, instead of the expected calming effect of social interaction with the owner, the effect was...
The occurrence and the function of aggressive mimicry in the vertebrates
Sommerová, Tereza ; Fuchs, Roman (advisor) ; Pipek, Pavel (referee)
Aggressive mimicry is used by a predator or parasite to deceive a potential prey or host. This bachelor thesis briefly summarizes other similar definitions of this phenomenon a then focuses on the species,especially vertebrates, that are included under this category. The use of the aggressive mimicry by fish of the families Blenniidae, Serranidae, Antennariidae, Labridae a snakes of the families Viperidae, Elapidae a Colubridae is described in more detail. Key worlds: aggressive mimicry, Peckhamian mimicry, caudal luring, toe/pedal luring, lingual luring
Responses of naive primates to snakes: experiments with selected species kept in Prague zoo
Kutinová, Lucie ; Frynta, Daniel (advisor) ; Fuchs, Roman (referee)
In the wild, snakes are known to elicit strong antipredator responses in primates. Primates often mob the snakes, which is also accompanied by loud calls. In evolution, the deadly threat posed by snakes goes as far as to the origin of placental mammals. In this study, the reactions of naïve individuals to snakes were tested. Naïve pigtail macaques (Macaca nemestrina) and mouse lemurs (Microcebus murinus) avoided the snake stimulus. For the macaques there was a longer latency to touch the rubber snake compared to the latency to touch the rubber lizard. The mouse lemurs avoided feeding on the side of experimental box where the snake odor was presented. The reactions of macaques and mouse lemurs were not accompanied by vocalizations and they seemed to be overall mild. Nevertheless, the snake stimuli used here were strong enough for these naïve primates. For ringtail lemurs (Lemur catta), the reactions to uncovering a hidden rubber snake was tested. But the lemurs showed no avoiding reactions. A question for further research is whether the different results for lemurs were not caused by different experimental procedure. As well as in macaques and mouse lemurs, the reactions seemed to be very mild. But no deeper analysis of the behavior was performed. Thus, a reaction could have been overlooked, which...
The acoustic detection of potential predator in domestic horse (Equus caballus)
Vidimská, Tereza ; Komárková, Martina (advisor) ; Fuchs, Roman (referee)
Equidae belong to a group of large herbivores, which survival in natural environment depends beside others on their capability of fast predator recognition and detection. They can sensually recognise a possible threat in advance and react by immediate escape, which increases their survival. Also domestic horses still show very sensitive reaction to sudden (unexpected) stimuli. So we assume, that the ability to detect predator immediately is conserved despite of the long domestication process. The supportive indirect evidence is given by the successful breeding of the feral herds all over the world. However, studies showing the direct reaction of domestic horse toward the canids (as the most common predators), are still absent. Aim of the work was to find, if the horses (Equus caballus) could recognize acoustic sign of dogs like predators and if they could recognize the level of potential threat according to the number of predators, similarly as their wild ancestors. The recordings of barking of big dog breeds were obtained and modified. The final recording contained the set of barking coming from one individual or three different. The recording was played to the experimental horses, under controlled conditions, together with white sound as a control. The reactions were recorded. Altogether 12...
Biology of three-toed woodpecker
Navrátil, Martin ; Fuchs, Roman (advisor) ; Reif, Jiří (referee)
In my thesis I have tried to find out how does forest management influence presence of the Three-toed woodpecker Picoides tridactylus.This species is considered a "flagship species" of an untouched primeval type of forest and therefore it requires our attention and protection. The thesis contains results of North-American studies focused on the species very similar to Picoides tridactylus. The main chapters are those aimed to provide information about how is the Picoides tridactylus affected by forest fragmentation, stand health condition and finally the impact of food supply on the occurence and behaviour of the species.
Signaling between ungulates and their predators, depending on the degree of predation pressure
Vidimská, Tereza ; Komárková, Martina (advisor) ; Fuchs, Roman (referee)
The Equids are large grazers inhabiting the savannah and prairies throughout the world. They have two types of social organization, the harem or the territorial, depending on the natural environment where they live. Main predators are the large felids and canids, especially these hunting together in packs. Historically humans were also the important hunters, based on the rich archeological evidence. Fast escape is the primary antipredation strategy of equids. This strategy is supported by many morphological, anatomical and behavioral adaptations. The body construction allows them to flee immediately and to run for a long distance. Their senses are evolved extraordinary as well, primarily the olfactory and vision. The early predator detection, enhanced by the broad interspecies communication, significantly increases the chance of horses, zebras and asses for successful survival.

National Repository of Grey Literature : 81 records found   1 - 10nextend  jump to record:
Interested in being notified about new results for this query?
Subscribe to the RSS feed.