Coauthor Irina Rotenko
Until wolf pups are about one month old, they stay mainly at dens being taken care of by parents who stay at the den or, at least, in the close proximity. Then wolf pups begin to be more mobile, but very hidden life of a wolf family in the tall and dense vegetation makes hard to learn the pup behaviour in June-July. The topic of wolf pups life when they are about 30-100 days old is still very poorly known in Europe and the whole Eurasia. Smart and careful usage of camera-traps can help in studying the question, while telemetry does not seem to be a right method in this case. In our study, besides camera-trapping we also used several other sources of data that are mentioned below in the post.
Applying camera-traps, in order to discover a spot of wolf family stay in June-July demands a lot of time and specific knowledge and skills. Generally, the studying process of wolf family behaviour in June-July (wolf pups are 30-100 days old in this period) is very time-consuming and not well-reportable. Therefore, wolf researchers can get relatively little results on the question in this hard-working period.
In this post we report the results of our multiannual efforts to investigate the question mainly in Naliboki Forest, central-western Belarus, but also in Paazierre Forest in northern Belarus. The basic method was installing (in special suitable points, but not on pathways only) camera-traps (up to 70) as well as searching for the place of wolf family stay and learning something on the question there. Our up-to-date results are following.
After the busy period of denning, when early days pups mostly feed on mother milk, a new and markedly different situation in the wolf family starts. The pups need milk less and less and begin to consume some solid food, mostly meat brought by the parents in their stomachs. The pups become more and more mobile. Wolf pups of one month old are registered walking themselves alone 300-500 meters away of the point, where parents leave them, when go for foraging. Simultaneously, their parents leave pups alone more and more frequently and are absent for longer time.
At this situation the following interesting questions need to be raised. At which age of the pups does the lactation start to decline? At which age do pups begin to eat solid food? At which age of pups does the weaning happens? What is the habitat structure in the wolf family homesites in June-July? How much time does wolf family stay in one particular homesite? How often do wolf parents relocate pups? What is the role of father? How often a subordinated pup-sitter is present at a wolf litter? How far do wolf pups walk from the homesite centre in June-July? How do wolf parents try to provide shelter and security for pups in June-July?
Again, it is likely to emphasize that we did not find any substantial publication related to the above questions for wild-living wolves in the European forest zone. Of course, there are a lot of studies conducted on these questions in North America (Mech & Boitani, 2003 and references therein), but the American and European wolves are greatly different both in behaviour and ecologically.
At the same time, although we advanced quite a lot in investigating of the raised questions, we still haven’t answered on any one of them entirely. However, there is a worthwhile knowledge on the topic to share.
For 13 times in the period of the mid-May-June (age of pups up to 60 days) we faced with situations, when pups of known age (they were found by us at dens before) ate solid food i.e. meat that was brought by parents in their stomachs. Another source of information was the carcasses of wolf mothers (n=6) and pups (n=89), which were killed by hunters in the period of May till the mid-July. In half of these cases we knew more or less the age of the pups (e.g. before the pups were killed by a hunter we found the den with the pups of early days) .
These irregular data suggest strongly that the duration and importance of the lactation depends on the food base. While comparing a few cases in the conditions of very rich and poor prey supply, the duration the of lactation by wolf mothers was almost double different. We evidenced that for pups of about 40 days old the mother’s milk was already not so important in the conditions of rich food base and the mother secreted milk only a little bit. But, when prey were scarce, pups of almost 70 days old were nursed and the mother was still strongly milk-secreting. The killed pups had meat in the stomach since the age of 20-25 days old, and the stomachs of pups of 40-60 days old rarely contained milk and were filled with meat.
With finishing the lactation phase, a wolf family starts moving markedly more i.e. more often and on longer distances each time. While adverting to this period in wolf families, researches frequently use the term of a ‘rendezvous site’ and distinguished this from a resting site (e.g. Theuerkauf et al., 2003). The authors of the article defined ‘rendezvous sites’ as places, where young wolves stayed for several days and to which the adults returned regularly, and resting sites as places, where wolves rested once for an hour or longer. We evaluate these different definitions as too sophisticated, and avoid to use them. In our quite big dataset (51 wolf families were more or less followed during summer) we faced with the following.
Sometimes, wolf parents left the pups shortly in a particular place, came back and picked the pups up. It is something negligible, and it does not mean that it should be named somehow with a particular term. Indeed, nobody terms a random place, where a wolf defecated once. We think that such a short stay of pups in a particular place means that something was wrong with the choice or the family was making a too long relocating. Other places, where parents leave their pups, were used longer and in such a place parents spend much time (hours) every day. Fairly often parents rest few hundred meters away from this pup locations, controlling the situation around the litter and avoiding disturbance from too active pups. Well trampled resting couches of parents, photos and videos from camera-traps indicated this habit many times. So, both rendezvous and resting sites occur altogether, and we assume that it is quite reasonable. We call such a place the wolf family homesite.
It is interesting to know how long a wolf family may stay in a given homesite. Checking that with camera-trapping and howling, we are sure that it can be quite long. In one case, the wolf family stayed mainly in a few hectares plot within tall grass stands at drainage canals for two months, at least. Another such case of about two months stay of wolf family with pups was documented on the relatively large forested island in the place of small river split. Spruce forest with several glades were mainly used by the wolf family on the island. Moreover, this island was regularly visited by the wolf family till mid December. Another similar case, but this time in the mosaic of grass stands and willow bush thickets at drainage canals, the wolf family stayed about 40 days. Another long stay of wolf family was detected in extended treefall (five neighboring treefalls in the area of about 40 hectares), where the family lived from the denning in the late April till the end of September, i.e. five months. However, usually (more than for half of the cases) wolf families used homesites for 5-12 days only.
Hardly predictable result was that already in July (usually age of pups are 70-90 days) wolf pups walked up to 2 km away from the homesite centre alone or in groups 2-5 pups without any parents. This free walking behaviour of pups in so early days old was registered common in July. Respectively, when the parent wolves brought food in their stomachs, only few pups that appeared nearby were fed. A bit later they were registered by cameras with full bellies, whereas other pups were with almost empty stomach.
In June-July we did not register that parent wolves brought a prey in the homesite centre. They plausibly avoid that smelling of spoiling carcass will attract other animals that may be inimical for the pups. So, in most of the cases parent wolves bring food for pups in their stomach. Brining of carcass or prey part happens later in August-September, when the pups are not so vulnerable. However, quite often parent wolves locate pups for fairly long (e.g. 7-12 days) not far away from the relatively by prey like red deer or elk calf.
Avoiding smelling in June-July, parent wolves collect the pup scats. Parents carry the pup scats in their stomachs (like in a bag) away, where they drop all of them by vomiting. We occasionally learnt this in Paazierre Forest in the late June of 2003, when a mother wolf was killed by a hunter from a hide in the proximity of the den. There were pup’s excrements in its stomach. We immediately realized that was the reason, why we normally could only find some scats at the wolf homesite with pups. Later in Naliboki Forest, we discovered wolf vomiting twice with many scats of pups, and we easily recognized it.
In June-July in a wolf family homesite the parent wolves try to eliminate all the red foxes and scare lynxes, red deer and elks. They avoid to be in the close proximity with housing areas of bison herd and brown bear. If it is impossible, parent wolves may relocate pups away from the forested habitats in open grassland or field with rue or maize. The latter we registered twice in Naliboki Forest in 2019.
Also, to save pups, when there are many inimical animals in the homesite surroundings, parent wolves may subordinate one or even two non-breeding females that are relative or non-relative. That phenomenon was documented assuredly for two times in Naliboki Forest in 2018 and 2020 with help of camera-traps. To provide better security for pups, parent wolves dig many burrows in the long-living homesite. In the case of pack multi-breeding several (two or three) subfamilies may join in June-July, and together they are able to provide safer homesite scaring lynxes and wild ungulates.
By tracing wolf family life with camera-traps in Naliboki Forest, we found that all the cares about pups (except of nursing with milk) are fulfilled by both partners i.e. the mother and father.
In June-July we found the wolf family homesites (n=104) in the following habitats or microhabitats:
(1) High grass stands with some bushes or without any bush usually on abandoned drained lands (mainly at drainage canals with wolf burrows in canal banks) – 14(11) times, 13.5(10.6)%;
(2) Willow bush thickets – 4 times, 3.8%;
(3) Large treefalls – 11 times, 10.6%;
(4) Some treefalls in an old spruce forests – 17 times, 16.3%;
(5) Fern stands in young forests – 3 times, 2.9%;
(6) Wolf burrow sites, i.e. where several wolf burrows are situated in a small area up to 10 ha, it includes former badger setts with enlarged entrances; usually such wolf burrows were created in sheltered biotopes (quite often that was in abandoned peatories) – 24(9) times, 23.1(8.6)%;
(7) Logging areas with a lot of tree remnants and early reforestation – 16 times, 15.4%;
(8) Rye or maize fields – 3 times, 2.9%;
(9) Thickets of grass and dead tree material in abandoned beaver settlements; there were many beaver burrows in such places – 8 times, 7.7%.
(11) Young spruce thicket with some open spots – 4 times, 3.8%.
Taking into account possible factors and wolf demands for a family homesite, we noticed that all of them were well sheltered somehow. When there were plenty of mosquitos, the homesites of 1, 6, 8, 9 and 10 were mainly used by wolf families. During rainy weather the homesites of 3, 4, 6 and 10 were used more frequently. In the pup raising period after the weaning phase, the distance from the wolf family homesite to the nearest road and the frequency of wild ungulate presence in the homesite were not important in contrast to the denning period. As to presence of people (e.g. collectors of mushrooms or berries), we noticed that the influence was a particular family-related, because we found so different patterns of homesite location in relation to human disturbance. Once, parents immediately reacted on our visiting of their homesite by escaping with pups during the first night, whereas the others persistently stayed in the same well-sheltered homesite despite of the repeated visits of us and mushroom collectors. Actually, the first pattern of such a response was usual, while the second one was registered for three times only. In two situations there were young spruce thickets with some fallen trees and several wolf burrows, and in one case it was an extended treefall.
In July in a wolf family homesite quite often both adults and pups use open grounds (sand or dry peat) to groom (resting and playing) with lower number of mosquitos and flies. Optimal for a wolf family, when at such a grooming spot on an open ground there is some swimming and drinking place.
In June-July, when pups are still very vulnerable, parent wolves do not mark much. If they mark, only urinating is applied for that, whereas they mark by scratching fairly rarely. In this period parent wolves normally avoid to walk by road much, they just cross them in most of the cases. Howling to call pups is applied by parent wolves, but in our quite large study experience that happens not so much as it was published in the wolf literature. In this period howling nearby wolf family homesite means calling by parent wolves with an alarm message. Normally parent wolves, while bringing food, search for pups by smelling. Of course, not all pups are fed in this case, but this clever approach forces pups to be as much as possible in the homesite, where parents left them.