Male guinea pig is frantic after introducing young female

[NumNums]

Hello. We neutered our male guinea pig almost 3 weeks ago, and he has been living alone for quite some time until now. We do not know his exact age but he is definitely more than 2 years old.
We got a new, young female (apparently 3 months old, but from an unreliable source) as a friend yesterday, but have been keeping her in a separate cage alongside his as per most internet forum recommendations.
Since being alerted to the presence of the new piggy our male has been somewhat frantic. He is 'wheeking' and groaning constantly, and even attempting in vain to bite through the side of the cage to try and get to the new piggy.
We aren't sure whether to interpret this behaviour as aggression, excitement, 'hornyness', or something else.
Does anyone have any ideas of what's going on?

 

[Wiebke]

Hello. We neutered our male guinea pig almost 3 weeks ago, and he has been living alone for quite some time until now. We do not know his exact age but he is definitely more than 2 years old.
We got a new, young female (apparently 3 months old, but from an unreliable source) as a friend yesterday, but have been keeping her in a separate cage alongside his as per most internet forum recommendations.
Since being alerted to the presence of the new piggy our male has been somewhat frantic. He is 'wheeking' and groaning constantly, and even attempting in vain to bite through the side of the cage to try and get to the new piggy.
We aren't sure whether to interpret this behaviour as aggression, excitement, 'hornyness', or something else.
Does anyone have any ideas of what's going on?

Hi and welcome!

Any boar will react to the presence of sow pheromones, especially when it is the first time they meet a sow since they were a baby. That is a normal reaction.

Please wait until 6 weeks before introducing. The little baby in my avatar picture is the unplanned legacy of a supposedly safe over 5 weeks neutered boar (not one of mine), just to make the point.
Here is our bonding information, which looks at behaviours, dynamics and particulars of different bondings (including mixed gender intros) through all the stages of the bonding process, which lasts well beyond the introduction and also including the preparation.
Bonding and Interaction: Illustrated social behaviours and bonding dynamics

If there is a health issue during the next three weeks (quarantining period), you will have to treat both piggies if they are next to other.
What to check and look out for in new guinea pigs (vet checks, sexing, parasites&illness)