Mars subsidiary Whistle, known for its pet trackers, will cease operations as it's being acquired by Tractive. Whistle pet trackers will stop functioning on August 31, 2025. Tractive is offering a free replacement tracker to affected users who request one by September 30, 2025, providing their Whistle tracker's serial number. Tractive will also credit pre-paid Whistle subscriptions to new Tractive accounts. Users without active subscriptions will receive two months of free Tractive service. Whistle's devices utilized GPS, Wi-Fi, and AT&T's network for tracking.