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Jensen, P. (2023). Hundens hemligheter: om vanliga men oförklarliga beteenden. Stockholm: Natur & Kultur
Open this publication in new window or tab >>Hundens hemligheter: om vanliga men oförklarliga beteenden
2023 (English)Book (Other (popular science, discussion, etc.))
Abstract [sv]

Har du undrat varför hundar gärna äter märkliga saker, som gräs eller bajs? Eller varför de rullar sig i stinkande högar och lägger så mycket tid på att leka och sova? På ett lättläst och pedagogiskt sätt tar Per Jensen upp dessa och en rad andra hittills obesvarade gåtor och presenterar, med humor och en stor kärlek till hundar, hur vetenskapen försökt lösa dem.[Bokinfo]

Place, publisher, year, edition, pages
Stockholm: Natur & Kultur, 2023. p. 191
Keywords
Hundar, Hundpsykologi, Etologi
National Category
Behavioral Sciences Biology
Identifiers
urn:nbn:se:liu:diva-191816 (URN)9789127181496 (ISBN)
Available from: 2023-02-16 Created: 2023-02-16 Last updated: 2023-12-28Bibliographically approved
van Poucke, E., Hoglin, A., Jensen, P. & Roth, L. (2022). Breed group differences in the unsolvable problem task: herding dogs prefer their owner, while solitary hunting dogs seek stranger proximity. Animal Cognition, 25(3), 597-603
Open this publication in new window or tab >>Breed group differences in the unsolvable problem task: herding dogs prefer their owner, while solitary hunting dogs seek stranger proximity
2022 (English)In: Animal Cognition, ISSN 1435-9448, E-ISSN 1435-9456, Vol. 25, no 3, p. 597-603Article in journal (Refereed) Published
Abstract [en]

The communicating skills of dogs are well documented and especially their contact-seeking behaviours towards humans. The aim of this study was to use the unsolvable problem paradigm to investigate differences between breed groups in their contact-seeking behaviours towards their owner and a stranger. Twenty-four dogs of ancient breeds, 58 herding dogs, and 17 solitary hunting dogs were included in the study, and their behaviour when presented with an unsolvable problem task (UPT) was recorded for 3 min. All breed groups interacted with the test apparatus the same amount of time, but the herding dogs showed a longer gaze duration towards their owner compared to the other groups and they also preferred to interact with their owner instead of a stranger. Interestingly, the solitary hunting dogs were more in stranger proximity than the other groups, and they also showed a preference to make contact with a stranger instead of their owner. Hence, we found differences in contact-seeking behaviours, reflecting the dog-human relationship, between breed groups that might not only be related to their genetic similarity to wolves, but also due to the specific breeding history of the dogs.

Place, publisher, year, edition, pages
Springer Heidelberg, 2022
Keywords
Dog; Dog-human relationship; Contact-seeking behaviour; Unsolvable problem task
National Category
Psychology (excluding Applied Psychology)
Identifiers
urn:nbn:se:liu:diva-181466 (URN)10.1007/s10071-021-01582-5 (DOI)000720188100001 ()34792653 (PubMedID)
Note

Funding Agencies|Linkoping University; Agria/Swedish kennel club [N20160020]; Svelands Stiftelse

Available from: 2021-11-30 Created: 2021-11-30 Last updated: 2023-12-28
Hedlund, L., Van Poucke, E. & Jensen, P. (2022). Can Early Environmental Enrichment Buffer Stress from Commercial Hatchery Processing in Laying Hens?. Poultry, 1(2), 125-137
Open this publication in new window or tab >>Can Early Environmental Enrichment Buffer Stress from Commercial Hatchery Processing in Laying Hens?
2022 (English)In: Poultry, E-ISSN 2674-1164, Vol. 1, no 2, p. 125-137Article in journal (Refereed) Published
Abstract [en]

Under commercial conditions, laying hen chicks are exposed to a range of stressful events immediately after hatch. Here, we studied whether environmental enrichment was able to reduce the stress sensitivity of these chicks. A total of 50 hatchery chicks (HC) and 50 control chicks (CC) were raised in enriched pens (E), while 53 HC + 53 CC were raised in standard non-enriched floor pens (NE). HC weighed less on day one, but there was no effect of hatchery treatment at later ages. HC were more pessimistic in a cognitive judgement bias test and emitted more distress calls when socially isolated, indicating that hatchery stress affected behaviour and stress sensitivity. However, enrichment did not affect the behaviour in any of these tests. We found no effects of hatchery stress in a novel environment, but indications that enrichment may have increased fearfulness of HC. The sensitivity of the hypothalamic-pituitary-adrenal (HPA) axis was reduced in HC-E compared to HC-NE, indicating that enrichment buffered the physiological stress sensitivity in HC; however, the opposite pattern was found in CC. In conclusion, our results show complex and somewhat contradictory effects on the ability of enrichment to buffer the consequences of stress in commercial hatcheries.

Place, publisher, year, edition, pages
MDPI, 2022
Keywords
hatchery stress; white leghorn; enrichment; corticosterone; behaviour; early stress
National Category
Biological Sciences
Identifiers
urn:nbn:se:liu:diva-188040 (URN)10.3390/poultry1020011 (DOI)
Funder
Swedish Research Council Formas, 2016-01728Swedish Research Council Formas, 2019-02084
Available from: 2022-09-02 Created: 2022-09-02 Last updated: 2023-12-28
Rutkauskaite, A. & Jensen, P. (2022). Domestication effects on social information transfer in chickens. Animal Cognition, 25, 1473-1478
Open this publication in new window or tab >>Domestication effects on social information transfer in chickens
2022 (English)In: Animal Cognition, ISSN 1435-9448, E-ISSN 1435-9456, Vol. 25, p. 1473-1478Article in journal (Refereed) Published
Abstract [en]

Red junglefowl (RJF), ancestor of all domesticated chickens, is a highly social, omnivorous bird species, presumably with a capacity for social information sharing. During domestication, birds have been selected to live in large, dynamic groups, and this may have affected their social cognition. Here, we studied social information transfer in female RJF and domesticated White Leghorn (WL) chickens. Individuals were trained to open a puzzle-box feeder by pecking a lid and we then recorded the behaviour towards the same puzzle-box feeder for birds that had either observed the trained individual ("guided") or saw the puzzle-box feeder for the first time ("naive"). WL were considerably faster in approaching the feeder regardless of prior demonstration and pecked more at it. Both breeds were significantly faster to approach the puzzle-box feeder and pecked more after prior demonstration, but the effects were significantly stronger in WL. We conclude that both RJF and WL can utilize social information to address a novel problem, but during domestication this ability appears to have increased. The effects can be an effect of either social learning or stimulus enhancement. Some caution in this conclusion is necessary since we tested relatively few WL. Furthermore, possible confounding explanations include higher fearfulness in RJF and different effects of dominance interactions between demonstrators and observers.

Place, publisher, year, edition, pages
Springer Heidelberg, 2022
Keywords
Domestication; Problem-solving; Stimulus enhancement
National Category
Psychology (excluding Applied Psychology)
Identifiers
urn:nbn:se:liu:diva-184999 (URN)10.1007/s10071-022-01628-2 (DOI)000790719600002 ()35507205 (PubMedID)
Note

Funding Agencies|Linkoping University - Swedish Research Council [1019-04869]

Available from: 2022-05-17 Created: 2022-05-17 Last updated: 2023-12-28Bibliographically approved
Hedlund, L. & Jensen, P. (2022). Effects of stress during commercial hatching on growth, egg production and feather pecking in laying hens. PLOS ONE, 17(1)
Open this publication in new window or tab >>Effects of stress during commercial hatching on growth, egg production and feather pecking in laying hens
2022 (English)In: PLOS ONE, E-ISSN 1932-6203, Vol. 17, no 1Article in journal (Refereed) Published
Abstract [en]

Every year, billions of egg layer chicks around the world are hatched under highly stressful, industrial circumstances. Here, it is investigated how the stressful procedure in the commercial hatchery, including incubation, hatching, processing, and transport affects the chicks with regards to traits relevant for the egg production industry. These traits were compared to those of a control group hatched in a small incubator and handled gently och quietly in a quiet room without any processing and transport. The chicks were weighed at hatch and at eight additional time points: 4 days, 1 week (w), 2 w, 3 w, 5 w, 8 w, 20 w and 25 w of age. Feather pecking was studied at 15 w of age and damages to the feathers and injuries on the comb and wattle were assessed at 25 w of age. From 19 w of age, eggs were collected on three days per week, counted and weighed. Chicks from a commercial hatchery had a lower hatch weight than control chicks (p<0.001). At 20 w of age, the weight of the commercial hatched chicks was still numerically lower, although this did not reach statistical significance. Commercially hatched chicks tended to show more feather pecking behaviour at 15 w of age compared to control chicks (p<0.1), although feather condition at 25 w of age showed the opposite pattern. Regarding production, commercially hatched chickens laid fewer (p<0.05) and smaller (p<0.05) eggs than chicks hatched and handled under calm circumstances. From this experiment, it is concluded that the stressful experience in the commercial hatchery has an overall negative effect on traits relevant for the industry.

Place, publisher, year, edition, pages
San Francisco, CA, United States: Public Library of Science, 2022
National Category
Ecology
Identifiers
urn:nbn:se:liu:diva-184293 (URN)10.1371/journal.pone.0262307 (DOI)000834805700029 ()34982788 (PubMedID)2-s2.0-85122215690 (Scopus ID)
Funder
Swedish Research Council Formas, 2016-01728
Note

Funding: FORMAS [2016-01728]

Available from: 2022-04-11 Created: 2022-04-11 Last updated: 2023-12-28Bibliographically approved
Rezaei, S., Uffenorde, J., Gimm, O., Hosseinpour Feizi, M. A., Miemczyk, S., Coutinho, L. L., . . . Pértille, F. (2022). GBS-MeDIP: A protocol for parallel identification of genetic and epigenetic variation in the same reduced fraction of genomes across individuals. STAR Protocols, 3(1), Article ID 101202.
Open this publication in new window or tab >>GBS-MeDIP: A protocol for parallel identification of genetic and epigenetic variation in the same reduced fraction of genomes across individuals
Show others...
2022 (English)In: STAR Protocols, ISSN 2666-1667, Vol. 3, no 1, article id 101202Article in journal (Refereed) Published
Abstract [en]

Summary:The GBS-MeDIP protocol combines two previously described techniques, Genotype-by-Sequencing (GBS) and Methylated-DNA-Immunoprecipitation (MeDIP). Our method allows for parallel and cost-efficient interrogation of genetic and methylomic variants in the DNA of many reduced genomes, taking advantage of the barcoding of DNA samples performed in the GBS and the subsequent creation of DNA pools, then used as an input for the MeDIP. The GBS-MeDIP is particularly suitable to identify genetic and methylomic biomarkers when resources for whole genome interrogation are lacking.

Place, publisher, year, edition, pages
Cell Press, 2022
National Category
Computer and Information Sciences Biological Sciences Basic Medicine
Identifiers
urn:nbn:se:liu:diva-188044 (URN)10.1016/j.xpro.2022.101202 (DOI)
Available from: 2022-09-02 Created: 2022-09-02 Last updated: 2023-12-28Bibliographically approved
Gabrielle, L., Rebecca, O., Hedlund, L., Gjöen, J. & Jensen, P. (2022). Play ontogeny in young chickens is affected by domestication and early stress. Scientific Reports, 12(1), Article ID 13576.
Open this publication in new window or tab >>Play ontogeny in young chickens is affected by domestication and early stress
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2022 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 12, no 1, article id 13576Article in journal (Refereed) Published
Abstract [en]

Play is common in young homeotherm animals and has an important role as a tentative indicator of positive states of welfare. Furthermore, during domestication play is believed to have increased in frequency in several species as part of the domestication syndrome. Here, we studied the ontogeny of play in chickens in two experiments. The first compared the behavioural development between domesticated White Leghorn (WL) laying hen chicks and ancestral Red Junglefowl (RJF) and the second compared the same between WL chicks that had experienced the stress of commercial hatchery routines and a control group, hatched under calm conditions. In both experiments, 10 groups of four chicks each from each of the groups were moved twice per week to an enriched and fully enclosed play arena, starting at day 8 and finishing day 39 or 53 after hatch. In the arena, the frequency of play behaviours was recorded during 30 min and divided into object, locomotory and social play. In experiment one, total play as well as object play was significantly more common in WL whereas locomotor and social play was more common in RJF. In experiment two, total play was significantly more frequent in commercially hatched chicks, despite that none of the sub-categories differed significantly between the groups. In conclusion, domestication as well as early stress does affect the occurrence of play in chickens, but the effects are complex and require further research.

Place, publisher, year, edition, pages
NATURE PORTFOLIO, 2022
National Category
Zoology
Identifiers
urn:nbn:se:liu:diva-187875 (URN)10.1038/s41598-022-17617-x (DOI)000839487700013 ()35945259 (PubMedID)
Note

Funding Agencies|Formas research agency [2016-01728, 2019-02084]; Swedish Research Council [2019-04869]

Available from: 2022-08-31 Created: 2022-08-31 Last updated: 2023-12-28
Katajamaa, R., Wright, D., Henriksen, R. & Jensen, P. (2021). Cerebellum size is related to fear memory and domestication of chickens.. Biology Letters, 17(2), Article ID 20200790.
Open this publication in new window or tab >>Cerebellum size is related to fear memory and domestication of chickens.
2021 (English)In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 17, no 2, article id 20200790Article in journal (Refereed) Published
Abstract [en]

Red Junglefowl (Gallus gallus) were selected for divergent levels of fear of humans during eight generations, causing the selection lines to differ in fear levels as well as in the proportional brain and cerebellum masses. Birds from the two lines were then crossed to obtain an F3 intercross in order to study the correlations between brain mass and fear learning. We exposed 105 F3-animals individually to a fear habituation and memory test at 8 days of age, where the reactions to repeated light flashes were assessed on 2 consecutive days. After culling, the absolute and relative sizes of each of four brain regions were measured. Stepwise regression was used to analyse the effects of the size of each brain region on habituation and memory. There were no effects of any brain region on the habituation on day one. However, birds with a larger absolute size of cerebellum had significantly reduced reactions to the fearful stimuli on day two, indicating a better memory of the stimuli. No other regions had significant effects. We conclude that increased cerebellum size may have been important in facilitating chicken domestication, allowing them to adapt to a life with humans.

Place, publisher, year, edition, pages
The Royal Society, 2021
Keywords
brain, chicken, domestication
National Category
Behavioral Sciences Biology
Identifiers
urn:nbn:se:liu:diva-176021 (URN)10.1098/rsbl.2020.0790 (DOI)33529547 (PubMedID)
Available from: 2021-06-01 Created: 2021-06-01 Last updated: 2023-12-28
Jensen, P. (2021). Hundens språk och tankar. Stockholm: Natur & Kultur
Open this publication in new window or tab >>Hundens språk och tankar
2021 (Swedish)Book (Other (popular science, discussion, etc.))
Abstract [en]

Det är svårt att tänka sig ett mänskligt liv utan hundar! Sedan vi levde som jägare och samlare har hunden följt oss människor. Per Jensen, professor i etologi, har skrivit en bok om hundens beteende, språk och tankeförmåga och beskriver pedagogiskt hur kunskapsläget är idag. Ny fakta blir här tillgänglig för en intresserad allmänhet.

Place, publisher, year, edition, pages
Stockholm: Natur & Kultur, 2021. p. 215
Keywords
Hundar, Etologi
National Category
Animal and Dairy Science
Identifiers
urn:nbn:se:liu:diva-176984 (URN)9789127172746 (ISBN)
Available from: 2021-06-22 Created: 2021-06-22 Last updated: 2023-12-28Bibliographically approved
Katajamaa, R. & Jensen, P. (2021). Tameness correlates with domestication related traits in a Red Junglefowl intercross. Genes, Brain and Behavior, 20(3), Article ID e12704.
Open this publication in new window or tab >>Tameness correlates with domestication related traits in a Red Junglefowl intercross
2021 (English)In: Genes, Brain and Behavior, ISSN 1601-1848, E-ISSN 1601-183X, Vol. 20, no 3, article id e12704Article in journal (Refereed) Published
Abstract [en]

Early animal domestication may have been driven by selection on tameness. Selection on only tameness can bring about correlated selection responses in other traits, not intentionally selected upon, which may be one cause of the domesticated phenotype. We predicted that genetically reduced fear towards humans in Red Junglefowl, ancestors of domesticated chickens, would be correlated to other traits included in the domesticated phenotype. Fear level was determined by a standardised behaviour test, where the reaction towards an approaching human was recorded. We first selected birds for eight generations for either high or low fear levels in this test, to create two divergent selection lines. An F3 intercross, with birds from the eighth generation as parentals, was generated to study correlations between fear-of-human scores and other unselected phenotypes, possibly caused by pleiotropy or linkage. Low fear-of-human scores were associated with higher body weight and growth rates, and with increased activity in an open field test, indicating less general fearfulness. In females, low fear-of-human scores were also associated with more efficient fear habituation and in males with an increased tendency to emit food calls in a mirror test, indicating increased social dominance. Low fear-of-human scores were also associated with smaller brain relative to body weight, and with larger cerebrum relative to total brain weight in females. All these effects are in line with the changes observed in domesticated chickens compared to their ancestors, and we conclude that tameness may have been a driving factor underlying some aspects of the domesticated phenotype.

Place, publisher, year, edition, pages
Wiley-Blackwell Publishing Inc., 2021
Keywords
chickens, correlated selection responses, domestication, fear behaviour, tameness
National Category
Behavioral Sciences Biology
Identifiers
urn:nbn:se:liu:diva-170840 (URN)10.1111/gbb.12704 (DOI)000579123300001 ()32969588 (PubMedID)2-s2.0-85092315416 (Scopus ID)
Funder
Swedish Research Council, 2015‐05444
Note

Funding agencies: VetenskapsradetSwedish Research Council [2015-05444]

Available from: 2020-10-26 Created: 2020-10-26 Last updated: 2023-12-28Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5491-0649

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