GORILLA MOMS 2 - Proximity and Elevation Changes

While collecting behavior data on each of the mothers, as I recorded what she was doing every thirty seconds, I also recorded if she was in proximity to another group member, whether she was outside or inside, and if she was in an elevated place in the enclosure.  It seemed these might change after the infant was born.

Regarding proximity, would the mother keep more distance from other individuals to protect her baby?  Would other group members seek proximity to the infant out of curiosity?  Would the silverback maintain greater proximity to look out for the mother and baby?  Would the mother seek out the silverback for protection?

Four proximity categories were used:  touch (physical contact), arm (within one adult female arm's reach), close (within one to two arm lengths), far (beyond two arm lengths).

Regarding location in the enclosures, would the new mother spend more time in elevated areas, perhaps to protect her baby?  Or would she spend less time up on platforms, etc. because it was a challenge to climb with an infant in tow?  

As expected, all proximities of group members to Jo increased after Jabali was born (postpartum).  What I didn't expect was for the total proximity increases for each of Jo's adult group mates to be so similar.  The only exception was a decrease in the time Angel was within one arm's reach of Jo.  This makes sense, given Angel's aggression, and suggests Jo may have been limiting proximity to Angel for Jabali's protection. 

Subjectively it seemed that Jim and Angel's increased proximity to Jo reflected their interest in Jabali.  Jim's touching Jo involved a play/grooming session initiated by Jim and terminated by Jo.  Bassa had previous experience with Jo's infants, suggesting that her increased proximity might have more to do with guarding Jo and Jabali from Angel.

Also as expected, total proximity of all adults to Jo decreased after a few months, with Jim's decrease being less than Bassa or Angel's.  Also, one would expect Jabali to spend more time farther away from Jo as she matured and became more independent.

Postpartum, both Kelly and Rapunzel initiated proximity to each other.  As time passed, Kelly was the one seeking proximity to Rapunzel.  This suggests Rapunzel had sought proximity to him postpartum for protection of Tinga.  Or perhaps she just wanted to share Tinga with him.

Evelyn's proximity to Rapunzel decreased dramatically postpartum.  Kelly and Evelyn didn't get along, so when Kelly was in proximity to Rapunzel, Evelyn was farther away.  As Kelly began to spend less time close to Rapunzel, this allowed Evelyn and Rapunzel to increase their proximity.

After Tumani was born, Rafiki spent more time in proximity to Asha, and the other females kept more distance.  There were two connected indoor exhibits, and Rafiki was often with Asha and Tumani while the other three females were in the adjoining exhibit.  When Asha and Tumani were in elevated spots inside, Rafiki was usually on the floor below them.

Initially Asha tended to move away if Rafiki came close.  When Tumani was 10 days old, Rafiki seemed to decide it was time for him to check out his daughter.  He had been in the nest he constructed near Asha.  He got up and approached Asha, who moved away.  He approached her again, she moved away.  This continued for several attempts, Rafiki moving slowly and quietly, but determined.  Asha soon realized this was going to happen and stayed put as Rafiki approached.  Ever so gently he touched his lips to the top of Tumani's head and smelled her.  That was it.  Then he moved away.  It was one of the sweetest gorilla moments I've ever seen.  

Even though Rafiki's proximity to Asha decreased during the final phase, both Rafiki and Asha did continue to seek proximity to each other.  Rafiki might nest near Asha, or she might sit beside him.

Juju, Tumani's grandmother, had been keeping her distance, but during the last phase her curiosity seemed to get the best of her.  Hers was the only proximity to Asha that increased.  One day she edged closer to Asha and was watching Tumani.  Tumani approached Juju, who was mesmerized (photo above).  When Tumani reached out to touch Juju, Asha quickly reached for Tumani, and Juju jumped a mile!  

Postpartum:  

For all three females, proximity to the infant's father increased postpartum.  This makes sense, given a silverback's protective role, and will be discussed more in Gorilla Moms 3.  Jo and Asha spent significantly more time in proximity to their silverbacks.  So perhaps we should not expect there to be a difference between experienced and new mothers.  Jo's proximity to other group females also increased postpartum, but Tinga's and Asha's decreased.  Perhaps we can expect experienced mothers to be more tolerant of the proximity of group females. 

7-8.5 Months Postpartum:

We might expect a mother's proximity to other group members to decrease over time, and that was generally the case here.  This is probably due to the "novelty" of the new infant wearing off. Or the other group members may still be interested, but the infant itself is spending less time near mom.  Another factor seems to be the comfort level of other females with the silverback, e.g. Evelyn and Juju.  As the silverback spent less time in proximity to the mother and infant, their proximity increased. 

Although amount of change varied, all three females spent less time in elevated spots in their enclosures after their infants were born.  This could be due to the logistics of climbing with a clinging infant who also needed some support.  Although, I must say it was amazing to watch the moms maneuvering this so well!  (see photo above of Asha climbing while carrying Tumani on her belly)  The postpartum decrease could have also reflected the energy drain of climbing while carrying a child. 

The increase in time in elevated areas as their infants matured seems to support the first hypothesis, but not the second.  The moms were still carrying their infants a lot, and it would require even more energy to carry a heavier child.  Moms also could have been spending more time in elevated spots in pursuit of their adventurous offspring!

The vast majority of time in elevated areas for all three females occurred inside, where they had access to nets, shelves, platforms, fire hoses, and logs.  I therefore thought changes in time spent in elevated areas might correspond with changes in time spent indoors, rather than the infants' increasing mobility and independence, but that was not the case for any of the females.

The two Denver groups alternated outside and indoors.  During all phases of data collection, when inside in the more confined space, the silverback of each troop tended to be terrestrial and the females more arboreal.