u/Individual-Plant4067

We recently got 4 gerbils from a pet shop (first time we got gerbils, and also first time getting animals from a shop - all our guinea pigs came from rescue shelters). We were told they're all sisters, but we have a suspicion one of them might actually be a male. He/she sometimes jumps atop his sisters. They are 9-10 weeks old now. We took a photo tonight, I hope it's good enough for the experts here to tell us if it's a male or female (it's the 2nd picture, to comply with the spoiler rule). Thanks in advance!