Zootopia Wiki

The Night howler sickness, often referred to as "going savage", is an affliction in mammals caused by poisonous flowers called Midnicampum Holicithias, more commonly known as "Night howlers", which causes those afflicted to go "savage", losing all semblance of rationality and attacking all around them.

There have been seventeen known sufferers of this sickness, including the fourteen Missing mammals, jaguar Renato Manchas, and Judy Hopps' uncle, Terry Hopps. While the effects can occur from ingestion of the plant, they probably wear off after a while, while in its more concentrated form, the effects can last for a very long time.

It is revealed that the Night howler sickness has been being transmitted artificially by Assistant Mayor Bellwether as part of a plot to induce fear of predators.

Signs and Symptoms

Night Howler sickness generally manifests itself within moments of exposure to some form of the Night Howler plant. In the main plot of the film, a more concentrated dosage of Night Howler serum is used to induce immediate and violent effects, though in the case of Judy Hopps' Uncle Terry, it is unknown exactly how soon effects began, though they manifested themselves fairly similarly, causing Terry to go berserk and attack Bonnie Hopps, taking a "sizeable divot" out of her arm. Symptoms of the sickness include:

  • Violent convulsions
  • Fits of mania
  • Unprovoked and irrational violence
  • Loss of sanity, sentience, and self-control
  • Reversion to primitive instinct and typical animalistic behavior

Notably, the reversion to primitive instinct does not seem to develop beyond traditionally violent and predatory behaviors, as there appears to be no concept of caution in the behavior of affected mammals. An example is Emmitt Otterton, who, while first under the effects of the sickness, did not at all seem fazed by Renato Manchas, who is a jaguar and thus a much larger and more dominant predator.

In its base form, Night Howlers may only cause these symptoms for a relatively short period of time. An example of this is how Judy's Uncle Terry is referred to, as it is not consistent with a narrative involving death or continued suffering from the sickness.

However, in a concentrated form, only brought about by artificial distilling of liquified Night Howlers, and therefore entirely artificial in nature also, the effects appear to last for much longer, possibly indefinitely. Dawn Bellwether, the mastermind behind the operation, seems to assume that the effects will last for a while, as she is apparently unfazed by any ideas that sufferers will recover from their sickness.


Initially, Night Howler sickness was only transmitted by internal contact with the plant Midnicampum Holicithias, commonly referred to as Night Howlers. Contact was most common in the form of ingesting, though that may not be the sole method of transmission.

However, in May, another method of transmission, involving a dart gun with pellets containing a serum of liquified and distilled Night Howlers, was developed and led to a large-scale outbreak of the sickness.

Notable incidents

Night Howler Conspiracy

During the month of May, various cases of Night Howler sickness erupted throughout Zootopia, with an initial 14 afflictions. The Mayor of Zootopia, Leodore Lionheart, was quick to keep the outbreaks hushed up, assembling a team of elite wolf guards to capture the afflicted mammals and keep them contained in Cliffside Asylum until a cure could be found. Judy Hopps, one of the newest officers in the Zootopia Police Department, the police force tasked with finding the mammals in what was assumed to be a string of missing mammal cases, discovered the mammals in the asylum, leading to the arrest of Mayor Lionheart and the asylum's staff. Since the mammals affected were all predators, it was assumed by both Dr. Madge Honey Badger, the Doctor tasked with analyzing the patients, and Judy herself to be down to biology, and that the predators were simply reverting to a more primitive state.

After the arrest of Lionheart, a number of other cases of Night Howler Sickness erupted over the next few months, with still no cure in sight. However, Judy later discovered the link between Night howlers and the affected predators after learning of the incident with Terry. This discovery led to the further discovery that the sickness was artificially spread. Judy teamed up again with fox Nick Wilde, following leads to the underground lab of Doug Ramses, a ram scientist who had been cultivating and weaponizing Night Howlers, and subsequently exposing their liquefied toxin to the unwitting victims via paintball-like pellets fired by an air-powered sniper gun. They finally implicated Assistant Mayor Bellwether in the spreading of the sickness and the commissioning of Doug as part of a conspiracy to alienate predators and have prey dominate the city. Bellwether shot Nick with the serum gun to make him kill Judy, and he appeared to do so, but it was later revealed that Nick swapped the serum pellets with blueberries and Judy recorded Bellwether's confession with her Carrot pen. The treacherous mayor was then arrested by Chief Bogo and the ZPD and imprisoned for conspiracy, fraud, and terrorism.


Once the cause of the outbreak was narrowed down to Night howlers, Zootopia's medical scientists and chemists began development of a cure to treat the afflicted predators.

Known Cases