Editing Beaver (section)

==Behavior==
{{multiple image
| width             = 220
| direction         = vertical
| image1            = Beaver family upper Los Gatos Creek 2008 Mercury Freedom.jpg
| caption1          = North American beaver family, with the center pair grooming one another.
| image2            = Tayside Beaver mother and kit June 5, 2010 Ray Scott.jpg
| caption2          = Eurasian beaver parent and kit.
}}

Beavers are mainly [[nocturnality|nocturnal]] and [[Crepuscular animal|crepuscular]], and spend the daytime in their shelters. In northern latitudes, beaver activity is decoupled from the [[Circadian rhythm|24-hour cycle]] during the winter, and may last as long as 29 hours. They do not [[hibernate]] during winter, and spend much of their time in their lodges.<ref name="MacDonald"/><ref name=JohnHopkins/>{{sfn|Runtz|2015|p=76}}

===Family life===
The core of beaver social organization is the family, which is composed of an adult male and an adult female in a [[Pair bond|monogamous pair]] and their offspring.<ref name="MacDonald"/><ref name=Pelagic/> Beaver families can have as many as ten members; groups about this size require multiple lodges.{{sfn|Müller-Schwarze|Sun|2003|pp=30–31}} [[Mutual grooming]] and play fighting maintain bonds between family members, and aggression between them is uncommon.<ref name=Pelagic/>

Adult beavers mate with their partners, though partner replacement appears to be common. A beaver that loses its partner will wait for another one to come by. [[Estrus]] cycles begin in late December and peak in mid-January. Females may have two to four estrus cycles per season, each lasting 12–24 hours. The pair typically mate in the water and to a lesser extent in the lodge, for half a minute to three minutes.{{sfn|Müller-Schwarze|Sun|2003|pp=80, 85}}

Up to four young, or kits, are born in spring and summer, after a three or four-month [[gestation]].<ref name="Pelagic" />{{sfn|Müller-Schwarze|Sun|2003|p=80}} Newborn beavers are [[precocial]] with a full fur coat, and can open their eyes within days of birth.<ref name="JohnHopkins" /><ref name="Pelagic" /> Their mother is the primary caretaker, while their father maintains the territory.<ref name="MacDonald" /> Older siblings from a previous litter also play a role.{{sfn|Müller-Schwarze|Sun|2003|pp=32–33}}

After they are born, the kits spend their first one to two months in the lodge. Kits suckle for as long as three months, but can eat solid food within their second week and rely on their parents and older siblings to bring it to them. Eventually, beaver kits explore outside the lodge and forage on their own, but may follow an older relative and hold onto their backs.<ref name="Pelagic" /> After their first year, young beavers help their families with construction.<ref name="MacDonald" /> Beavers sexually mature around 1.5–3 years.<ref name="JohnHopkins" /> They become independent at two years old, but remain with their parents for an extra year or more during times of food shortage, high population density, or drought.{{sfn|Müller-Schwarze|Sun|2003|pp=332–333, 100–101}}<ref>{{cite journal|last1=Mayer|first1=M|last2=Zedrosser|first2=A|last3=Rosell|first3=F|year=2017|title=When to leave: the timing of natal dispersal in a large, monogamous rodent, the Eurasian beaver|journal=Animal Behaviour|volume=123|pages=375–382|doi=10.1016/j.anbehav.2016.11.020|s2cid=53183887}}</ref>

===Territories and spacing===
[[File:Castor fiber vistulanus2.jpg|thumb|left|alt=A beaver on a water bank|[[Eurasian beaver]] near its dam.]]
Beavers typically disperse from their parental colonies during the spring or when the winter snow melts. They often travel less than {{convert|5|km|mi|0|abbr=on}}, but long-distance dispersals are not uncommon when previous colonizers have already exploited local resources. Beavers are able to travel greater distances when free-flowing water is available. Individuals may meet their mates during the dispersal stage, and the pair travel together. It may take them weeks or months to reach their final destination; longer distances may require several years.{{sfn|Müller-Schwarze|Sun|2003|pp=101–103}}<ref>{{cite journal|last1=McNew|first1=L. B.|last2=Woolf|first2=A.|year=2005|title=Dispersal and Survival of Juvenile Beavers (''Castor canadensis'') in Southern Illinois|journal=The American Midland Naturalist|volume=154|issue=1|pages=217–228|doi=10.1674/0003-0031(2005)154[0217:DASOJB]2.0.CO;2|jstor=3566630|s2cid=86432359 }}</ref> Beavers establish and defend [[Territory (animal)|territories]] along the banks of their ponds, which may be {{convert|1|–|7|km|1|abbr=on}} in length.<ref>{{cite journal|last1=Graf|first1=P. M.|last2=Mayer|first2=M.|last3=Zedrosser|first3=A.|last4=Hackländer|first4=K.|last5=Rosell|first5=F.|year=2016|title=Territory size and age explain movement patterns in the Eurasian beaver|journal=Mammalian Biology – Zeitschrift für Säugetierkunde|volume=81|issue=6|pages=587–594|doi=10.1016/j.mambio.2016.07.046|bibcode=2016MamBi..81..587G }}</ref>

Beavers mark their territories by constructing scent mounds made of mud and vegetation, scented with castoreum.{{sfn|Runtz|2015|p=128}} Those with many territorial neighbors create more scent mounds. Scent marking increases in spring, during the dispersal of yearlings, to deter interlopers.<ref name="Rosell 1997">{{cite journal | last1=Rosell | first1=Frank | last2=Nolet | first2=Bart A. | year=1997 | title=Factors Affecting Scent-Marking Behavior in Eurasian Beaver (''Castor fiber'') | journal=[[Journal of Chemical Ecology]] | volume=23 | issue=3 | pages=673–689 | doi=10.1023/B:JOEC.0000006403.74674.8a | bibcode=1997JCEco..23..673R | hdl=11250/2438031 | s2cid=31782872 | hdl-access=free }}</ref> Beavers are generally intolerant of intruders and fights may result in deep bites to the sides, rump, and tail.<ref name=Pelagic/> They exhibit a behavior known as the "[[dear enemy effect]]"; a territory-holder will investigate and become familiar with the scents of its neighbors and react more aggressively to the scents of strangers passing by.<ref name="Bjorkoyli 2002">{{cite journal|last1=Bjorkoyli|first1=Tore|last2=Rosell|first2=Frank|year=2002|title=A Test of the Dear Enemy Phenomenon in the Eurasian Beaver|journal=[[Animal Behaviour (journal)|Animal Behaviour]]|volume=63|issue=6|pages=1073–1078|doi=10.1006/anbe.2002.3010|hdl=11250/2437993|s2cid=53160345|hdl-access=free}}</ref> Beavers are also more tolerant of individuals that are their kin. They recognize them by using their keen sense of smell to detect differences in the composition of anal gland secretions. Anal gland secretion profiles are more similar among relatives than unrelated individuals.<ref name= "Lixing 1998">{{cite journal | last1=Sun | first1=Lixing | last2=Muller-Schwarze | first2=Dietland | year=1998 | title=Anal Gland Secretion Codes for Relatedness in the Beaver, ''Castor canadensis'' | journal=[[Ethology (journal)|Ethology]] | volume=104 | issue=11| pages=917–927 | doi=10.1111/j.1439-0310.1998.tb00041.x| bibcode=1998Ethol.104..917S }}</ref><ref>{{cite journal|last1=Sun | first1=Lixing | last2=Muller-Schwarze | first2=Dietland |year=1997|title=Sibling recognition in the beaver: A field test for phenotype matching|journal=Animal Behaviour|volume=54|issue=3|pages=493–502|doi=10.1006/anbe.1996.0440| pmid=9299035 | s2cid=33128765 }}</ref>

===Communication===
Beavers within a family greet each other with whines. Kits will attract the attention of adults with mews, squeaks, and cries. Defensive beavers produce a hissing growl and gnash their teeth.<ref name=Pelagic/> Tail slaps, which involve an animal hitting the water surface with its tail, serve as alarm signals warning other beavers of a potential threat. An adult's tail slap is more successful in alerting others, who will escape into the lodge or deeper water. Juveniles have not yet learned the proper use of a tail slap, and hence are normally ignored.{{sfn|Runtz|2015|pp=55–57}}{{sfn|Müller-Schwarze|Sun|2003|pp=48–49}} Eurasian beavers have been recorded using a territorial "stick display", which involves individuals holding up a stick and bouncing in shallow water.{{sfn|Runtz|2015|p=133}}