Cannibalism

Feather sucking, or feather licking, has been reported anecdotally by employees in the Australian meat chicken breeder industry, but scarcely in the scientific literature. Consequently, the causes and implications of this behavior in meat chicken breeding chickens is relatively unknown. We surveyed 17 industry experts to generate hypotheses about feather sucking behavior. We aimed to understand the frequency and when it occurs, and attempted to understand what may cause an "outbreak". The recruitment of participants was intentionally biased towards Australian perspectives; only 5 of the 17 participants were international...

Cells in obligately multicellular organisms by definition have aligned fitness interests, minimum conflict, and cannot reproduce independently. However, some cells eat other cells within the same body, sometimes called cell cannibalism. Such cell-in-cell events have not been thoroughly discussed in the framework of major transitions to multicellularity. We performed a systematic screening of 508 articles, from which we chose 115 relevant articles in a search for cell-in-cell events across the tree of life, the age of cell-in-cell-related genes, and whether cell-in-cell events are associated with normal multicellular development or cancer...

The wild boar ( Sus scrofa ) is a social animal species native to Eurasia. During the last decade, the wild boar population in Estonia has been severely affected by the African swine fever virus (ASFV), which has also affected domestic pig farming. The potential transmission routes of ASFV remain unclear and are currently under intensive investigation. This pilot study aimed to clarify the frequency and characteristics of contacts between living wild boars and the carcasses of their conspecifics, which could play a role in the transmission of ASFV...

Injurious behaviors (i.e., aggressive pecking, feather pecking, and cannibalism) in laying hens are a critical issue facing the egg industry due to increased social stress and related health and welfare issues as well as economic losses. In humans, stress-induced dysbiosis increases gut permeability, releasing various neuroactive factors, causing neuroinflammation and related neuropsychiatric disorders via the microbiota-gut-brain axis, and consequently increasing the frequency and intensity of aggression and violent behaviors...

AbstractThe adaptive value of routinely laying more eggs than can be successfully fledged has intrigued evolutionary biologists for decades. Extra eggs could, for instance, be adaptive as insurance against hatching failures. Moreover, because recent literature demonstrates that sibling cannibalism is frequent in the Eurasian hoopoe ( Upupa epops ), producing extra offspring that may be cannibalized by older siblings might also be adaptive in birds. Here, directed to explore this possibility in hoopoes, we performed a food supplementation experiment during the laying period and a clutch size manipulation during the hatching stage...

Japanese flounder Paralichthys olivaceus is one of the most valuable coastal flatfish species in East Asia. To investigate post-settlement growth and mortality, juveniles were sampled in Tango Bay (Japan) weekly throughout the settlement period in 2007 and 2008. Otolith (lapillus) microstructure analysis enabled the categorization of juveniles into six biweekly cohorts each year. Later cohorts exhibited higher growth rates possibly because of higher water temperatures. A key observation was the direct relationship between high mortality and high density in mid-season cohorts in both years, pointing to density-dependent mortality...

In this paper we examine the traditional mortuary rites of the South Fore people of Papua New Guinea using Robert Hertz's theory of secondary burial and the three mechanisms of mourning identified by Daniel Lagache. The ethnographic data that we obtained on South Fore interpretations of their own mortuary rites showed that all forms of corpse handling achieved the same end results through the process of secondary burial. Furthermore, the three mechanisms of mourning applied equally to all forms of corpse disposal and we found no evidence to support psychosexual interpretations of mortuary anthropophagy which emphasise aggression...

Many organisms can adjust their development according to environmental conditions, including the presence of conspecifics. Although this developmental plasticity is common in amphibians, its underlying molecular mechanisms remain largely unknown. Exposure during development to either 'cannibal cues' from older conspecifics, or 'alarm cues' from injured conspecifics, causes reduced growth and survival in cane toad ( Rhinella marina ) tadpoles. Epigenetic modifications, such as changes in DNA methylation patterns, are a plausible mechanism underlying these developmental plastic responses...

To date, numerous mechanisms have been identified in which one cell engulfs another, resulting in the creation of 'cell-in-cell' (CIC) structures, which subsequently cause cell death. One of the mechanisms of formation of these structures is entosis, which is presumably associated with possible carcinogenesis and tumour progression. The peculiarity of the process is that entotic cells themselves actively invade the host cell, and afterwards have several possible variants of fate. Entotic formations are structures where one cell is engulfed by another cell, creating a cell-in-cell structure...

Two forms of gigantism are differentiated in fish, Brobdingnagian and Goliathan gigantism, the former applying to populations whose individuals are all larger than is typical for the taxon, the latter to single individuals within a population. While Brobdingnagian gigantism is largely explained by various ecological and evolutionary rules, Goliathan gigantism is not. A mechanistic hypothesis is proposed which explains Goliathan gigantism in terms of the reduction of oxygen requirements of individual fish via moving to cooler temperatures and/or acquiring larger, more energy-dense prey, which enable them to get bigger, and, in the process, sometimes generate bimodal size distributions that may qualify as gradual forms between Goliathan and Brobdingnagian gigantism...

Animal welfare has evolved during the past decades to improve not only the quality of life of laboratory rodents but also the quality and reproducibility of scientific investigations. Bibliometric analysis has become an important tool to complete the current knowledge with academic databases. Our objective was to investigate whether scientific research on cannibalism/infanticide is connected with maternal aggression towards the offspring in laboratory rodents. To carry out our research, we performed a specific search for published articles on each concept...

Species coexistence in ecological communities is a central feature of biodiversity. Different concepts, i.e., contemporary niche theory, modern coexistence theory, and the unified neutral theory, have identified many building blocks of such ecological assemblies. However, other factors, such as phenotypic plasticity and stochastic inter-individual variation, have received little attention, in particular in animals. For example, how resource polyphenisms resulting in predator-prey interactions affect coexistence is currently unknown...

Inducible defences can improve survival in variable environments by allowing individuals to produce defences if they detect predators. These defences are often expressed as inter-related developmental, morphological, and behavioural changes. However, producing defences can incur costs, which may be expressed immediately and/or during subsequent life stages. In Australia, waterborne cues of potentially cannibalistic conspecific tadpoles induce hatchlings of invasive cane toads to accelerate their developmental rate, thereby reducing their window of vulnerability...

INTRODUCTION: Anti-mitosis has been a key strategy of anti-cancer therapies, targeting at a fundamental property of cancer cells, their non-controllable proliferation due to overactive mitotic divisions. For improved anti-cancer therapies, it is important to find out whether cancer cells can proliferate independent of mitosis and become resistant to anti-mitotic agents. RESULTS: In this study, live-cell imaging was applied to both primary-cultures of tumor cells, and immortalized cancer cell lines, to detect aberrant proliferations...

1. Using chicken models to avoid unnecessary harm, this study examined the relationship between naturally-occurring maxillary (top) beak shapes and their ability to cause pecking damage.2. A selection of 24 Lohmann Brown laying hens from a total population of 100 were sorted into two groups based on their maxillary beak shape, where 12 were classified as having sharp beaks (SB) and 12 as having blunt beaks (BB).3. All hens were recorded six times in a test pen which contained a chicken model (foam block covered with feathered chicken skin) and a video camera...

This article explores the intriguing case of Kuru disease, a rare and fatal prion disease that once afflicted the Fore people of Papua New Guinea. Scientists are still perplexed as to the origins of Kuru because efforts to discover infectious agents like viruses have been ineffective. Initial research revealed similarities between Kuru and scrapie, a neurological disorder that affects sheep, suggesting potential similarities between the two diseases. In further research, experiments in which chimpanzee brain tissue from Kuru patients was implanted led to the development of Kuru-like symptoms in the animals, suggesting a transmissible component to the condition...

Maternal care is critically important for the survival of offspring in various animals. Spiders in the family Lycosidae are known for their hunting ability and maternal care behaviors. Predation on newly hatched spiderlings (pulli) by mother spiders decreases when they come into contact, and they carry the pulli on their dorsal surface. However, the factors inducing maternal care in lycosid spiders have not been elucidated. In this study, we investigated maternal care in Pardosa pseudoannulata (Araneae, Lycosidae) females...

Detecting declines and quantifying extinction risk of long-lived, highly fecund vertebrates, including fishes, reptiles, and amphibians, can be challenging. In addition to the false notion that large clutches always buffer against population declines, the imperiled status of long-lived species can often be masked by extinction debt, wherein adults persist on the landscape for several years after populations cease to be viable. Here we develop a demographic model for the eastern hellbender (Cryptobranchus alleganiensis), an imperiled aquatic salamander with paternal care...

Amphibian declines are a global phenomenon but responses of populations to specific threats are often context dependent and mediated by individual physiological condition. Habitat degradation due to reduced riparian forest cover and parasitism are two threats facing the hellbender salamander ( Cryptobranchus alleganiensis ), but their potential to interact in nature remains largely unexplored. We investigated associations between forest cover, parasitic infection and physiology of hellbenders to test the hypotheses that physiological condition responds to infection and/or habitat degradation...

Female spiders and praying mantises are renowned for their cannibalism of male partners before, during, or after mating. While several hypotheses have been proposed to explain species-specific examples of sexual cannibalism, much variation remains unexplained, including why the timing of cannibalism varies across taxa. Here, I outline how sexually cannibalistic behaviour could evolve via sexually antagonistic selection as a type of behavioural resistance to male-imposed mating costs, and how such a generalisable interpretation provides a framework for understanding the evolution of both sexual cannibalism in females and anti-cannibalistic traits in males...