My observation this year (2024) as well as recollections and comparisons from last year’s experiences (2023) suggest that yearlings might play a highly important role in kit development.
It appears that yearlings take active part in the raising of the kits – supervising them near den and later accompanying them in exploration trips to other areas of the home range further from the natal den.
In fact, the only family that I have observed which did not have a yearling in 2023, also did not exhibit the same kit development pattern as the rest of the families (in 2023 and in 2024) whereby this kit stayed very close to the den, perhaps began leaving the den itself rather late and not once I observed it taking trips further than 20 metres from the den.
Such behaviour could also have been due to the particular individual’s personality and the personality could have been partly the result of early experiences, as the specific kit grew up to be a yearling, quite comfortable being on its own and enjoying its favourite hang-out where, during the autumn – winter – early spring period it could be encountered 90% of the time (this site is quite far from the natal den, on the edge of the family’s territory).
I find it very likely that the kit itself was very observant and prone to deep study of its environment (which provides plenty of excitement and probably also an array of fine-tuned physical activities taken in order to closely inspect areas and objects) but the entire experience of having stayed alone a lot, finding its own entertainment and examining its natal den site to the detail was apparently enjoyable enough to mimic such circumstances later in life.
However, clearly, the kit had not grown into a ‘loner’ as its favourite hang-out is, in fact, situated very close to its sister’s (? older sibling’s) territory and thence the kit can interact with two beaver families and even engage in the babysitting of two sets of kits.
As I mentioned before, this kit seemed to grow up without a yearling supervisor and yet I stated that this kit had an older sister living nearby.
Indeed, I never noticed a yearling-sized individual attending the kit in 2023, and those were just the two adults (mommy and daddy) swimming to and back from the den.
Yet, due to several circumstances, I do believe that the kit has an older sibling (see Beaver observation (May 19, 2024) – a subadult visiting two territories and two natal dens?).
How has this come about then?
My guess is that the subordinate individual (the sister) was already two years old (and not a yearling) in the spring of 2023 and she might have dispersed before the kit was even born or close to that time.
Perhaps no kits were born (or no kits survived) in this family in 2022.
It is possible that the kit’s parents might be rather old (they are very large, they appear highly skilled and their range is one of the best ranges on the river which indicates they have been among the first to settle there).
Older mothers might not give birth to litters every year or they might be affected by some environmental conditions differently than younger females (which is compensated for by their experience).
I did not really record the climatic conditions in the years of 2021 and 2022 and, as a result, I cannot make any assessments over the impact of weather on forage availability and other such factors of influence.
However, for example, in 2023, two families had only one kit (born or surviving to yearling stage) and both families seem to have elderly parents (in the other family, the adults are also extremely large).
As beavers live rather long, it is perhaps less risky to skip a year or to produce fewer kits if it meant that the individuals did not die, the home could be kept and that the overall lifetime productivity would still be adequate.
Thus, it is possible that no kits were born in the family in question in 2022.
This does not truly explain why the young female (perhaps two years old in 2023, born in 2021) dispersed in the first place if she could have enjoyed staying at her parents’ who had no yearlings on their range and only one kit to take care of (resources were not limited).
I believe that most if not all animals want to be useful.
The yearling beavers in 2024 seem just overexcited and, indeed, proud and devoted to take care of their younger siblings, especially, because it is quite obvious the parents would never be able to cope without the yearlings’ assistance.
In this old, experienced beaver family, in the year of 2023, another subordinate might not have been as needed as the parents might have been fully capable of attending to their sole kit and the kit was apparently prone to academic exploration rather than gamboling all along the river.
Maybe the two-year-old grasped the situation and she left to pursue other life goals.
In fact, I wonder if two-year-olds might have other types of tasks within the family structure.
I have observed another two-year-old this spring/summer who was investing heavily in acquiring a good fitness status and a decent body mass only to have currently disappeared for a while.
On one hand, this individual might have dispersed seeking a new territory.
Similarly, the two-year-old in the old parents’ family could have dispersed upon reckoning her family could make due without her and she might have failed in her intent returning back to her parents.
It is quite difficult to tell the difference between a failed dispersal event (the individual was not fortunate enough to settle anywhere and to find a mate) and a deliberate return.
It is also difficult to tell why the individual might have returned on purpose (it was only a foray vs. there was some ulterior motivation to this excursion outside of family’s range which befits with the entire family’s interests, i.e., the individual was on a mission).
Scientific studies in many species suggest the typical life cycle pattern whereby young individuals in many mammalian species, upon having reached maturity, leave their parents and never return.
However, I wonder whether this has been the historical strategy in the species to begin with because it is clear that most young adults (in healthy, saturated populations that have not been ravaged by hunting, disease etc.) will not be able to establish a new home, nor to find a mate (e.g., by joining an existing family).
Before dispersal was turned into an undertaking of the highest mortality risk (by humans), I believe that animals did not disperse as ‘irreversibly’ and that most dispersal events were forays combined with some other purpose which benefited the entire family.
For example, in beavers, two-year-olds or three-year-olds might have deliberately departed on extraterritorial excursions but their intent might not have been that of leaving forever.
Rather, the intent might have been that of exploring the situation outside of home and then returning (unless an opportunity was revealed to the individual which the individual then took).
This returning could have been not the result of a failed attempt to leave but rather it could have been planned for.
Perhaps the travelling individual was performing the mission of inspecting the population area, determining where related individuals dwelt (and maybe even siblings), assessed the resource status as well as some changes significant to beavers (e.g., alterations in the river channel and hydrology).
It is not easy to imagine how the individual could have reported back to its family but I find it probable that they did, on some level, perhaps by taking leadership in some activities that decided the future use of resources and family planning in order to adjust the family’s behaviour to the regional patterns.
Maybe, in the olden golden times (relatively so, as beavers have always been persecuted), the older subordinates were explorers with the task of investigative journalism on mind, and the separate beaver families made decisions based on the resource availability and other trends on a population level.
I also find it quite unlikely that many such mammals as beavers, wolves etc. settle in the first plot they came by.
It is believable that, given the opportunity, individuals would prefer to choose homes (which they would be taking care of and which would be taking care of them for decades) according to their personalities, experience on former range, physiology etc.
Thus, these explorers might have been able to assess the dispersal of suitable habitats along the river that befitted the individuals in their particular family.
Perhaps they might even not have taken all the opportunities for themselves but, e.g., helped their younger siblings (yearlings, two-year-olds) settle in appropriate, vacant habitats accompanying them to these new home sites the way yearlings accompany kits during exploratory trips along their own home range.
Be as it may, the kit’s sister evidently returned and engaged, once more, with her younger sibling who, essentially, settled very close to her (she was allotted a less optimal portion of her parental range).
It is not known when her mate arrived but it must have happened before the mating season and before the winter as the winter of 2023/24 was rather harsh and ice covered most of the river making travel impossible or extremely difficult.
It almost seems they arrived at the same time and I would not turn down a supposition that they arrived together which is an interesting notion as it would then ensue that this female found her mate and brought him back in order to ask for the parents’ blessing (also, in the form of a range).
I wonder if they had pair-bonded during her travels and maybe she did not even intend to stay long on her parents’ range but life happened and they had kits.
I also wonder whether she might not have another territory on her mind which was not vacant in 2023 yet.
Could the family move to this other home once it becomes available?
My other reason for believing that this female had not intended to disperse permanently was that she had not had the experience of raising kits while with her parents but this experience appears to be a vital part of yearling education.
She also seemed to be highly invested in her young sibling after her return which suggests she is not lacking at all in maternal interest.
I find it quite mysterious why she dispersed in the first place.
Maybe she thought that after returning, in the year of 2024, she might watch her parents’ kits alongside the kit of 2023 who would be a yearling in 2024.
It seems that at least two yearlings are needed to help raise two kits, and thus she might have relied she would still get the chance to acquire that part of her education.
In fact, I am not entirely certain when our upstream HES stopped operating but there were considerable changes in water regime in 2022/23 (there were fewer fluctuations due to the HES activity but the water level became altogether much lower) and I truly wonder whether this female travelled around to research the causes and to gather data on the new conditions.
This would even coincide with the mother’s unwillingness/inability to conceive/give birth in 2022 and perhaps her subadult daughter was preparing for a journey to assess the situation in early 2023 in order to bring back the news to the family.
Anyway, it seems to me that the two-year-olds might have responsibilities others than helping in the raising of the kits and that their family responsibilities involve travels outside of their home.
Meanwhile, the yearlings are clearly actively participating in kits’ development.
Not all of those nannying activities could be excursion-based.
In 2023, I also observed a yearling sitting by the natal den and watching the kit swimming laps nearby.
I believe that one of the tasks is to give the kits a sense of confidence.
It is one thing to be an older sibling and to bring the kits out on a trip where the yearling is the leader and the deciding party, and the setter of the rules.
And it is another thing to raise the kit in a manner whereby the yearling is only ‘a shadow’, guiding the kit and watching out for danger as well as for age-appropriate routes and activities but letting the kit make decisions and letting the kit set the pace, explore on their own etc.
The latter scenario is precisely what I have been observing in these beaver families.
The yearlings do not seem to dominate the kit and while the yearlings are in no way neglectful, they appear to watch the kit as it exercises or inspects objects/subjects of interest and pursues its intended activity, to lead in an unimposing manner (e.g., by swimming underwater while the kit is swimming on the surface level and steering itself to its own will).
My observations so far suggest that the yearlings are excellent nannies and teachers as they take charge over the kit in a manner that the kit can be in charge almost at all times.
And the kits are, indeed, very confident, determined, curious and capable of making their decisions and overcoming insecurities.
The yearlings seem very patient (e.g., watching the kit for prolonged periods of time while the kit is not doing anything overly exciting, nor the kit is engaging in active play with the older sibling) and capable of high levels of empathy (being able to tell where it would be easier for the kit to swim and where perhaps the kit might not be able to conquer the current yet etc.).
However, it also seems that it is not an easy job.
For example, on Jun 10 (2024), I observed a yearling and a kit.
I find it difficult to believe that the family’s natal den is located in that particular area and I think that the yearling had taken the kit to the yearlings’ favourite hang-out which also has a burrow.
This family has two yearlings and perhaps two or more kits but, that night, I only observed one kit and one yearling.
The yearling was keeping close to the den where it was probably seated comfortably.
The kit was swimming in and out of the den and exploring the shores on both sides of the river.
I could not help but wonder whether the yearlings in this family had split up the litter of their younger siblings in order to catch a break.
Thus, one of the yearlings was supervising the kit (who was exploring on its own but always in sight of the yearling) in the yearlings’ hang-out while the other yearling could have been near the natal den with the other kit(s) or elsewhere.
It is only June and I believe by the end of the summer, the yearlings will have become babysitters that any au pair programme could only dream to certificate as their own.
Notes by Ieva 