Strange piggy behavior?

[Gilbertonious]

Hi! I recently got two male guniea pigs from a neglectful owner. The third one passed away last month, and my dominant pig (Gilbert) has been showing strange behavior towards his friend Marty. He’s stalking him around, only to vibrate at him and then lay down and observe him. I’m not sure if he’s lonely, and upset that Marty isn’t the cuddly type. Other than two incidents regarding them fighting for dominance, they’re fine, and haven’t hurt each other since. Am I overthinking? Or Is this normal?

 

[Piggies&buns]

This sounds normal - rumblestrutting is a normal dominance behaviour. In a new environment they will need to re-establish their relationship so there will be quite a bit of dominance behaviour. However, mounting, rumbling, chasing are all things which boys will do their entire lives
Ensure they have a big enough space (it’s essential for two boys that there isn’t a lack of space) - 180cm x 60cm for two boys, two of every items and no enclosed hides (two exits only so no piggy can get cornered).
If there are full on, fur ball, rolling around fights between boars, then they need permanent separation as that is a break down in their relationship.

Dominance Behaviours In Guinea Pigs
A Comprehensive Guide to Guinea Pig Boars

 

[Wiebke]

Hi! I recently got two male guniea pigs from a neglectful owner. The third one passed away last month, and my dominant pig (Gilbert) has been showing strange behavior towards his friend Marty. He’s stalking him around, only to vibrate at him and then lay down and observe him. I’m not sure if he’s lonely, and upset that Marty isn’t the cuddly type. Other than two incidents regarding them fighting for dominance, they’re fine, and haven’t hurt each other since. Am I overthinking? Or Is this normal?

Hi and welcome!

I am very sorry for your loss. Guinea pigs need to re-establish their hierarchy after the loss of a member so you will see the classic rumble-strutting you are describing - which is very mild dominance behaviour by the way. Boars establish their own hierarchy peacefully between them by measuring up as to who has the most sonorous rumble and is the larger. They can also do this by mounting or trying to mount their partner (who may not tolerate that so there may be a little tussle).
Gilbert is just reinforcing his leadership and making sure that he is still the boss but there is nothing to it. It should die down again over the course of about 2 weeks at the most.

You may also find this this guide with pictures and videos here helpful in learning to spot and understand key social interactive behaviours: Bonding and Interaction: Illustrated social behaviours and bonding dynamics