Coming from someone who's seen these guys for almost a decade and a half now, it's really interesting to see how the herd has drifted apart over time. Initially, the four cows were a tight knit group and I very much imagine the expansion of each matriline has contributed to this. It's not unusual to see the two groups at opposite ends of the exhibit these days, and I feel they'd certainly make use of the new complex and space at Werribee very well.
Scientists in the wild note many large elephant herds often break up into their own smaller groups during the day, to feed and the like, before returning together eventually as the day goes on to interact and to sleep together. Most elephants in zoos don't get the opportunity to do this; but Werribee's complex will give them the opportunity to do so.
It’s interesting how both herds (Taronga and Melbourne) divided into friendship pairs based on age:
Porntip (1992) and Pak Boon (1992)
Thong Dee (1997) and Tang Mo (1999)
Mek Kepah (1974) and Dokkoon (1993)
Kulab (1993) and Num Oi (2001)
While personality is a significant factor in forming friendships (Auckland Zoo has had some very mis-matched personalities); it’s clear age is equally instrumental in how easily these bonds are formed. Roi-Yim may lack the confidence of his half-sisters, but as young elephant wanting to play, he still gets great enjoyment from their company; while Aiyara and Kati are the perfect match. It’ll be interesting to see if their bond continues to flourish into adulthood and motherhood; or whether they spend the majority of their time in their matrilinial herds.