松露是地下真菌的子实体，无法像蘑菇那样随风散播孢子，只能依赖被动物吃下后经消化排出。问题在于，主要取食者是啮齿类和鼩鼱等小型哺乳动物，其活动范围很小，孢子随粪便移动的距离有限，往往仍与母体竞争，难以实现有效扩散。这一机制在空间尺度上显得不足。

研究者因此提出“二次吞食”假说：捕食者吃下取食松露的小动物，孢子在第二次消化后再被排出，从而实现远距离传播。研究在明尼苏达东部和威斯康星南部40个地点采样，检查了小型哺乳动物的肠道，并收集了267份捕食者粪便，来自狼、郊狼、狐狸、山猫和渔貂等。分析发现，两类样本中存在相同的真菌孢子；尽管捕食者粪便中的孢子总量通常低于田鼠和松鼠，但与鼩鼱和老鼠相当，且几乎没有证据表明捕食者会直接取食松露。

传播距离的关键来自捕食者的活动范围与消化时间。文献显示，食物通过渔貂消化道约需9小时，通过狼需约17小时；无线电项圈数据显示，渔貂在此期间平均移动约2公里，狼约3.5公里。由此推断，松露的扩散依赖两次进食与两次消化，显著放大了传播尺度。这一残酷却高效的生态链条，解释了松露如何跨越小型动物的空间限制完成繁殖。

Truffles are underground fungal fruiting bodies that cannot disperse spores by wind; instead, spores spread only after being eaten and excreted. The problem is that primary consumers—small mammals like rodents and shrews—have tiny home ranges, so spores deposited in their faeces travel little distance and often compete with the parent fungus, limiting effective dispersal.

Researchers proposed a “secondary consumption” mechanism: predators eat the truffle-eating animals, and spores survive a second gut passage before being excreted farther away. Sampling at 40 sites in eastern Minnesota and southern Wisconsin examined small-mammal guts and 267 predator scat samples from wolves, coyotes, foxes, bobcats and fishers. The same fungal spores appeared in both. Although predator scats typically contained fewer spores than voles and squirrels, loads were similar to shrews and mice, and there is scant evidence that predators forage directly for truffles.

Distance comes from predator movement and digestion time. Literature indicates food passes through a fisher in about 9 hours and a wolf in about 17 hours; radio-collar data show fishers travel roughly 2km in that time, wolves about 3.5km. Thus, truffle dispersal relies on two meals and two digestive journeys, greatly extending spread beyond small-mammal ranges—a grisly but effective ecological strategy.