Time of birth
Four females gave birth during the dark period and the remaining six females between 05:30 and 11:00. We did not measure the duration of parturition, but as revealed by detailed observations, one female gave birth to a new pup 8 h after the first pup in the litter.
Behaviour
Three of the ten females observed had pups that were never seen moving. Two of the remaining seven females with moving pups had one pup that was never seen moving, and another of these females had two pups that were never seen moving. In five of the seven females with live pups, detailed M→S observations were possible to carry out for at least one pup per female. During these observations, the behaviour “mouth manipulation with moving pup” was never followed directly by “pup still”.
In the remaining two females, nest material, poor video quality or missing recordings made it impossible to see when the pups stopped moving. In the females with at least one live pup, time until the last pup was seen moving differed from 4.5 to 67 h after birth (Figure 2). No wounds were visually detected on intact pups during the video observations (example of dead pups in Figure 3), whereas partly eaten pups could be observed in six females.
Detailed M→S observations
Below follows a description of the five females where detailed M→S observations were obtained (A1 refers to a female in study A, etc.). During the M→S observations, all behaviours occurring during the observation period were recorded, but the only behaviours seen in the female where “activity in nest” and “mouth manipulation in nest”. On all occasions where the female behaviour “mouth manipulation in nest” was recorded, the pups were seen moving after these interactions.
A1: Parturition started at 6:30, June 5; three pups were born. At 19 h after birth, three pups were seen moving. It was not possible to determine when the two first pups died (poor video quality and partly missing recordings). The third pup died sometime between 31.5 (last seen moving) and 33.5 hours (first seen still, not moving again) after birth. Just before scoring this pups’ last movement the female was manipulating the pup shortly with her mouth but the pup continued to move after the manipulation. Hereafter the female was lying still in the nest, not interacting with the pup.
A2: Parturition started at 22:40, August 3; three pups were born. At 41 h 40 min postpartum, all pups were seen moving, but the first pup was seen dead 20 min later. Between this pups’ last movements and the first observation of the pup still, the female was seen manipulating pups with mouth at three occasions, but the manipulated pups were seen moving after these interactions. The behaviour “activity in nest” was seen on six occasions; it was however difficult to distinguish the pups during these recordings. The second pup was seen dead at 45.5 h after birth, and only one short “activity in nest” was registered between first and second pup was observed dead. The third pup was seen moving on several occasions and was rather active. However, the amount of movement dropped over time and the last movements detected were very small. The last movement was seen at 66 h 50 min after birth; 15 min later the pup was still and partly hidden under sawdust, no interaction between mother and pup was seen during this period.
A4: Parturition started at 05:33, September 7; five pups were born. Two pups were never seen moving. The first time a live born pup was seen dead was 16 h after birth. The last movement detected in this pup during scanning was at 15 h 10 min after birth and after this two mouth manipulations were recorded, but the pup moved again after this manipulation before it died. The second live pup moved at 23 h 45 min after birth, and 24 min later it was dead. No interaction between female and pup was seen during this period. The last pup movement was seen at 27 h 15 min after birth and this pup was dead 2 h 40 min later. The female was mainly lying still in the nest during this period. The behaviour “activity in nest” was recorded twice for the female after the last pup movement but there was no observed mouth manipulation.
A5: Parturition started at 9:00, August 31; four pups were born. The pups were only seen moving on three occasions. The first pup movement was detected 1 h after birth when one pup was seen opening its mouth. After this movement the female retrieved the pup to the nest and two occasions of mouth manipulation were recorded. The pup was still during these interactions. Two hours after parturition when the female was outside the nest, another small movement was seen in one pup. The female immediately returned to the nest and a short mouth manipulation with the pup was recorded. The female was also seen active in the nest on two occasions, but then remained still in the nest until leaving it again 20 min later; there were then no pup movements. The last pup movement was seen at 4.5 h after parturition, this movement was also very small and only the pup’s head was visible. Five minutes after this movement this pup was seen still and no interaction between the female and this pup was seen during this 5-min period. It was not possible to determine if the movements described came from the same pup or three different pups.
B1: Parturition started 07:40, August 28; three pups were born. At 23 h after birth, two pups were seen moving inside the nest; 1 h 15 min later the female pushed one still pup to the outer edge of the nest and started to eat the pup or the placenta (not possible to distinguish) a few minutes later. It was not possible to determine if this pup had previously moved. Ten minutes later one pup moved inside the nest and another still pup was seen next to the first still pup, but this pup was seen to move again after 20 min. The last pup movement was seen at 26 h 45 min after birth. Hereafter the female spent 4 h lying still in the nest, leaving it only very shortly. The pups were difficult to see and it was not possible to determine the exact time when each pup stopped moving, but at 31 h 10 min after birth two dead pups and one partly eaten pup was seen in the outer edge of the nest.
Additional observations
Several events observed that might be related to pup survival were noted as comments while scoring behaviour. In one female, the first pup was stuck for 1 h in the cervical canal during parturition. This pup was never seen moving and the female did not interact with the pup after it came loose. The female was outside the nest when the parturition started and during the following 30 min. Another female was lying outside the nest for several hours in a hunched posture, while the pups were spread around in the nest and still alive (Figure 4). This female also moved the nest and pups to a new location in the cage about 1.5 day after parturition, but moved it back to the original site 3 h later. Two females were observed performing maternal behaviour with still pups on several occasions (Figure 5). These interactions included licking pup (in mouth and anogenital region), retrieving pup to nest, and manipulating pup with paws. Both these females had pups that were seen moving after birth. During the interactions, one of the females had live pups in the nest while manipulating a dead pup whereas the other female had no moving pups left. Females were also seen eating dead pups in the nest while still having live pups in the nest.