Opinion by

Whether the plaintiffs’ mules, which were injured while being carried in a car on the defendant’s road, had been shipped under a special contract restricting the defendant’s liability as a carrier was a question in dispute at the trial. As the action *213was founded upon the common law liability of a carrier the burden of proof as to any limitation thereof rested with the defendant, and unless it was admitted or clearly established by proof the question was necessarily for the jury. That the preponderance of evidence was in favor of such a limitation would not have justified the court in treating it as an established fact. The question was properly submitted with full and accurate instructions as to the effect of such an agreement if found to exist. This disposes of the first assignment of error, and the remaining assignments may be considered together. They relate to the admission of testimony as to the cause of the injuries, and to the sufficiency of this testimony to sustain a finding for the plaintiffs.

The plaintiffs had a car load of young mules and colts shipped from Cynthiana, Ky., to Fleetwood, Pa. The car was received by the defendant from another railroad company at Harrisburg. When the car reached Fleetwood a number of the mules were found to be seriously injured. To meet any defense based upon the ground of a restricted contractual liability the plaintiffs assumed the burden of proving that the injuries resulted from negligence while the car was on defendant’s road and in charge of its employees. Testimony was presented to show that the animals were in good condition and uninjured when they were received at Harrisburg; that the injuries were of recent occurrence, and not such as the animals would have inflicted upon each other, except involuntarily if they were thrown down and trampled or jammed together by a collision or rough handling of the cars. Witnesses who had been for years engaged in shipping mules, who knew their habits and disposition and the causes likely to lead to their injury while on board cars, and who saw these mules when they were unloaded, were allowed to express their opinions as to the cause of the injuries. The value of their opinions was for the jury to determine, and we see no valid objection to admitting the testimony.

There was no evidence of an injurious accident to the train, nor was there any direct evidence of improper or negligent handling of the cars. Injury to the contents of a ear may however furnish ground for an inference of want of ordinary care in transportation: American Express Co. v. Sands, 55 Pa. 140; Grogan v. Adams Express Co., 114 Pa. 523; Phœnix Pot *214Works v. P. & L. E. R. R. Co., 139 Pa. 284; Buck v. Penna. R. R. Co., 150 Pa. 170; N. Y. C. & H. R. R. Co. v. Eby, 22 W. N. C. 92. There is no reason why this rule with proper limitations should not apply to animate objects. It of course would have no application in the case of injuries which are such as animals voluntarily inflict upon each other, or which cannot be accounted for, or which . can be satisfactorily explained on any other ground than that of negligence in managing the train; nor in cases of death from natural causes, or causes entirely unknown, as in Penna. R. R. Co. v. Raiordan, 119 Pa. 577.

The case on the facts was one of great doubt, but the jury was not left to mere conjecture. The testimony furnished the basis for an intelligent finding, and its submission was free from error.

The judgment is affirmed.